For the first time when he takes on Juan Carlos Ferrero on Centre Court on Wednesday.
The 22-year-old Briton plays Spanish wildcard Ferrero in the second match at about 1530 BST, with Lleyton Hewitt or Andy Roddick waiting in the last four.
Murray beat Ferrero comfortably in the Queen's Club semi-finals two weeks ago.
"Ferrero is a very tough player. He plays well on any surface - he's a former world number one," said Murray.
"In every match, regardless of who you're playing against, especially in an individual sport, anything can happen on the day.
"I played very well at Queen's but the courts here are a little bit different.
"If I play poorly, there's a good chance I'll lose against him. But I'll try my best to play well. If I do that, I've got a chance of winning."
HENMAN ON MURRAY
Ferrero is the perfect match-up for Murray as he doesn't have the same firepower as Wawrinka
Murray is trying to become the first British man to win the Wimbledon singles title since Fred Perry in 1936, and the first Scot ever to win a Grand Slam singles title.
And the interest in the Scot's progress is such that fans began queuing for the 500 tickets Centre Court tickets available over two days in advance.
His quarter-final follows what is likely to be a serve-dominated contest between second seed Roger Federer and Ivo Karlovic on Centre Court, where play begins at 1300 BST.
It means Murray and Ferrero should avoid the worst of the hot weather forecast for Wednesday, when it is set to be dry with temperatures topping 30C.
The Scot came through a four-hour battle against Stanislas Wawrinka to win his fourth-round match on Monday, finishing late at night in the tournament's first full floodlit match under Centre Court's new roof.
"I believe I can win Wimbledon," he said. "That's not changed since the first match, but I'm going to have to play great tennis to do it."
Pundit's Picks - Men's quarter-finals
Ferrero is a former world number one and French Open champion but the 29-year-old has slipped down the rankings and spoke recently about possibly retiring at the end of 2009.
However, a run to the last four at Queen's Club appears to have rejuvenated the Spaniard.
He has already beaten 10th seed Fernando Gonzalez and eighth seed Gilles Simon at Wimbledon, and is the first wildcard since eventual champion Goran Ivanisevic in 2001 to reach the last eight.
"I think right now I'm with a little bit more rhythm than at Queen's," said the Spaniard.
"And of course after the match I played against Murray, I learnt something. That is, I have to do my job and be aggressive all the time, because he likes to play on one level and then he changes the rhythm very fast.
"I think it's very difficult to play against him because of this, so I will try to be focused on my return, because his serve has been very, very big.

"If I want to win, of course it's going to be very difficult. He's at home and he wants to win and everybody wants him to win, so it's going to be tough, as every match is."
The winner of Murray-Ferrero will face Roddick or Hewitt, who will meet in the second match on Court One.
Former champion Hewitt is unseeded, and had to come back from a thigh injury and two-set deficit against Radek Stepanek in the previous round.
"I have loads of respect for Lleyton and what he's been able to accomplish," said Roddick, who has won his last four matches against the Australian.
"Everyone knows he's certainly capable of playing very, very well on this surface."
The first match on Court One sees fourth seed Novak Djokovic take on Tommy Haas, a repeat of the recent Halle final on grass, which the German won.
Opening proceedings on Centre Court is five-time champion Federer's encounter with Karlovic.
The 30-year-old Croat has hammered down 137 aces in his four matches so far.
But Federer, who has won eight of their nine meetings so far, said: "I like those sort of challenges.
"It's maybe not the most fun match to go through, but I like to beat this guy because he makes it hard to beat him. He's become an excellent player.
"He's not to be underestimated."

Louise Donington, Laura Blakeman and Lizzie Neave won gold in the women's K1 team event, ahead of Slovakia.
In Saturday's last event, the men's K1 team of Campbell Walsh, Richard Hounslow and Huw Swetnam added a second gold by less than a tenth of a second.
Britain also won men's C2 team silver, as well as bronze in the men's C2 individual event.
Neave reached the final of the women's individual K1 event but came last after a 50-second penalty for a missed gate.
Ollie Williams on Twitter
Tim Baillie's just drifted past, bronze medal proudly draped around his neck. Looks a bit small to me. The medal, not Tim
Our man at the slalom Euros
In the team events, Britain got off to a poor start as their team of David Florence, Mark Proctor and Daniel Goddard finished last in the men's C1 (canoe single) final, behind winners the Czech Republic, France, Germany and Poland.
But the women's K1 (kayak single) team of Donington, Blakeman and Neave produced an almost faultless performance in a time of 108.63.
They then watched anxiously as a hotly-tipped Slovakian team could only come home in 110.46, handing the British women gold.
"I have won a few silvers and bronzes but never gold at a major international event," said Blakeman.
"It's an achievement, especially given the quality of the competitors here, and I'm delighted.
"We stuck to our individual plans but had to adapt slightly to take other team members into account."
In the last run of the last event of the day, Britain wrapped up a second gold thanks to the K1 (kayak single) team of Walsh, Hounslow and Swetnam.
Despite an early two-second penalty, the trio thrilled their home crowd - attending the first major slalom event in the UK for 14 years - with a dash for gold.
They finished in a time of 94.62 seconds, just eight hundredths of a second ahead of second-placed Germany.
"I've had a good day," said Walsh. "I could see the line first and I let out a massive roar, but I wanted to make sure before I celebrated too much.
"The fans have been really loud - the good weather has brought them all out and it gives you a lot of confidence."
Hounslow added: "It's absolutely brilliant. We had a bit of a mistake at the top but it was amazing. We crossed the line and couldn't believe it, it was so close."
Britain's men's C2 (canoe double) team - comprising Baillie, Stott, Florence, Hounslow, Goddard and Colin Radmore - had earlier added silver.
The six men finished in 112.17 seconds, just outside the Czech Republic's winning time of 111.22, after France and Germany had both suffered 50-second penalties.
In the individual events, Florence and Hounslow - first to go in the men's C2 final - were dogged by a series of two-second penalties which left them well out of the running as the remaining nine pairs took to the course.
By contrast, Baillie and Stott put in an assured, confident run, holding their momentum but just failing to edge out the French pair of Damien Troquenet and Mathieu Voyemant.
Baillie and Stott held second place for a time, before a fine run from Pavel and Peter Hochschorner secured gold for the Slovakian brothers and pushed France down into second.
Czech duo Jaroslav Volf and Ondrej Stepanek, last to go, had their gold-medal hopes shattered by a 50-second time penalty for missing a gate.
"It was just really cool, a really nice feeling to have done it when there was so much building up to it," said Baillie.
"I had a lot of faith in us. I'm so glad we've managed to put our name on the map and I believe we deserve it."
Stott added: "London 2012 is tantalising - racing at home is a big deal.
"We're just going to drive forward. We don't know where it'll lead but we have a fascinating journey ahead of us."
Six pairs made it through the C2 final without registering any penalties, including the gold medal-winning Hochschorners, in a time of 101.20.
The second-placed French pair were just over two seconds back in 103.52, with Baillie and Stott taking bronze in a time of 104.37.
CANOEING CATEGORIES EXPLAINED
C1 - one-person kneeling canoe
C2 - two-person kneeling canoe
K1 - one-person seated kayak
A third British duo, Goddard and Colin Radmore, finished 15th in the semi-final and missed the final.
Earlier, 21-year-old Neave sailed through her women's K1 semi-final run in fine form, 2.5 seconds outside Slovakian Jana Dukatova's time of 103.07.
But her dreams of a European title were dashed by a missed gate in the final, which incurs a 50-second penalty.
Slovakia's reigning Olympic champion Elena Kaliska, 27, recorded a penalty-free time of 104.24 seconds to win gold, beating France's Emilie Fer, whose actual time of 101.60 seconds was tempered by two two-second penalties for touching gates.
Neave made it down the course in 111.39 seconds before her 50-second penalty was taken into account, leaving her a total time of 161.39.
The European Championships conclude on Sunday with the men's C1 (canoe single) semi-final and final.

World Snooker Championship Date: 18 April-4 May Venue: Crucible Theatre, SheffieldCoverage: Live coverage each day on BBC Two, BBC Red Button and BBC Sport website (UK only), updates on BBC Radio 5 Live.
Video - Higgins holds nerve against Cope
John Higgins recovered from 12-10 down to beat Jamie Cope in the final frame and earn a meeting with Mark Selby in the World Championship quarter-finals.
Higgins also needed to deal with a time-out in the final frame when a spectator required medical treatment.
"At 11-9 down it wasn't looking too good," the Scot told BBC Sport. "But I got a few texts from my wife and she spurred me on so that was great."
Selby, who beat 2006 champion Graeme Dott 13-10, had an easier match.
Higgins and Cope resumed on Monday level at 8-8 in their second-round tussle after a lively start to the match.
Higgins 'shattered' after epic win
The 23-year-old qualifier from Stoke started the strongest, taking an 11-9 lead at the mid-session interval with a break of 82 in the 20th frame.
The 1998 and 2007 champion hit back to win the next frame, but a run of 103 from Cope left him one frame away from a shock victory.
"I thought I'd got him at 12-10. But I just didn't take the chance," the world number 19, who upset Joe Perry in the first round, said later.
A break of 96 from Higgins reduced the deficit to 12-11, before he prevailed in a nervous 22nd frame after a brief delay while the first of two spectators received treatment for dehydration.

VettelRules
The drama was cranked up another notch when play was stopped for a second time early on in the decider, when neither player had scored a point, because of a fan fainting in the audience.
"It is very rare for that to happen once, but when it happens twice like that it is very hard to go out of the arena and keep positive," said Higgins, who knocked in a difficult red immediately on the players' return, en route to a match-clinching 80.
"I was telling myself I was going to pot it, and was envisaging it before we went back. I looked dead and buried but I managed to pull through, so I am over the moon."
Higgins returned to the table to build an intelligent break of 80 and reach his 10th quarter-final in 15 years at The Crucible.
"It's as if these things are sent to test you as a player," added Higgins.
Video - Selby ends Dott resistance
"Jamie is going to be feeling absolutely devastated but it will hold him in good stead. He'll come back again and there's no doubt in my mind that he'll win it [the title] one day, no problem."
Selby always had Dott at arm's length in their contest, but it was not plain sailing by any means.
Resuming in the morning 6-2 up, the duo shared the first eight frames of the day - leaving Selby with a 10-6 advantage going.
Dott continued the fight, winning three of the first four frames of the final session but when Selby rattled a tough blue into the middle pocket he stood one frame away from the next round on 12-9.
And though a break of 88 gave Dott the next frame, Selby pounced to claim the win when Dott missed a medium-length red into a baulk pocket.

Date: 30 March-5 April 2009 Venue: Beijing University Students Gymnasium Coverage: Results and reports on the BBC Sport website

O'Sullivan has won the Northern Ireland Trophy this season
Ronnie O'Sullivan fended off a determined challenge from Fergal O'Brien to secure a first-round victory at the China Open in Beijing.
The world number one came from 2-1 behind to take the match 5-3.
Stephen Hendry picked up a confidence boosting 5-3 victory over Englishman Robert Milkins.
There were also first round wins for Mark Selby, Mark King, Greame Dott and Shaun Murphy while Marco Fu suffered a shock defeat to China's Tian Pengfei.
O'Sullivan produced breaks of 55 and 54 to secure the victory and will now play 20-year-old Chinese player Xiao Guodong, who was a surprise first-round winner against Ding Junhui.
"At 3-3 I could have been on my way home, but experience tells me never to panic or worry," O'Sullivan told worldsnooker.com.
"I always have faith that if I can find another gear I can pull away, and turn a 50/50 situation into a 90/10 in my favour. If I play decent I always like my chances.
606: DEBATE
Your thoughts on the China Open
"I was a bit loose today, I haven't played many matches lately so it would be good to win a few here to get some match sharpness."
Seven-time Crucible winner Hendry, 40, will now face Ricky Walden in the next round.
Selby beat fellow Englishman Stephen Lee 5-1 to progress to the next round, while King heaped more misery on Welshman Mark Williams with a 5-2 win.
Shaun Murphy looked confident against Cao Xinlong as he lost just one frame to breeze through to a second round clash with Australian Neil Robertson.
Scotland's Graeme Dott also advanced to the second round overcoming China's Yu Delu, 5-3.
There was a Chinese winner though, and a surprise one, as 21-year-old Tian Pengfei overcame Hong Kong's Marco Fu 5-2.
England's Stuart Pettman beat Northern Ireland's Mark Allen 5-3 in Wednesday's early match.