Andy Murray faces the daunting challenge of defeating defending champion Rafael Nadal on Friday if he is to reach his first Wimbledon final.
The British number one has the chance to make up for defeat by Nadal in last year's semi-finals when they meet in Friday's second match on Centre Court.
Novak Djokovic and Jo-Wilfried Tsonga open play in the first semi-final, which begins at 1300 BST.
Victory will ensure the Serbian becomes world number one next week.
Having lost just one match in 2011, another win will mean Djokovic has done enough to overhaul Nadal at the top of the standings no matter how the Spaniard fares against Murray.
Nadal needs no extra motivation as he closes in on an 11th Grand Slam title and his third at the All England Club, where he is on a 19-match unbeaten run.
As the two-time champion, and with an 11-4 head-to-head record against Murray that includes wins at Wimbledon in 2010 and 2008, Nadal is a strong favourite once again.
Both men have had injury concerns during the tournament, Nadal to his foot and Murray his hip, but the two came through practice sessions at Wimbledon apparently unscathed on Thursday.
"I feel fine, I'm just looking forward to tomorrow now," Murray told BBC Sport after practising. "I'll do all the right preparation and recovery stuff and try and play my best tomorrow."
And the 24-year-old Scot is not intimidated by the prospect of another meeting with Nadal, as well as in that Wimbledon semi-final of 2010.
"I believe I can win against him," said Murray. "I had chances last year. I was a break up in the third set, had break point on my serve in the second set - I think there was only one break in the first set. We both played good tennis.
"I just have to have a better game plan. Sometimes it comes down to strategy, sometimes it comes down to having experience. I just have to go out there and play well, serve well, and believe I'll have a chance."
Murray, of course, can end Britain's long wait for a Wimbledon men's singles champion, and the first step to matching Fred Perry's achievement of 1936 will be to follow in the footsteps of the nation's last finalist, Bunny Austin in 1938.
"The chance to make a Wimbledon final is an opportunity to make history,"
"When I'm on the court I'm not thinking about my place in history but when I look back on my career, I'll want to see where I was in the grand scheme of things."
Asked to assess Murray's chances against Nadal, three-time champion and BBC Sport commentator John McEnroe said: "He's got plenty left in the tank and Lord knows, he's going to need it. Let's be frank, he's got to play the best match of his life and it will be a five-set win if he's going to do it.
"Rafa's a killer when he's out there - Murray's got to have that attitude when he goes out there."
Nadal is certainly taking nothing for granted, having lost to Murray in Grand Slams before - in the 2008 US Open semi-finals and the 2010 Australian Open quarter-finals.
"Every year is a different situation," said the 25-year-old Majorcan. "Last year I beat him here in the semi-finals but it was a very close match, even if it was in straight sets. In the second set he had a set point on his serve.
"So the match will be very difficult for me, I think he's playing at a very, very high level."
One concern for Nadal has been a foot injury picked up in his fourth-round win over Juan Martin del Potro that briefly threatened his continuing participation in the tournament, and it remains an issue.
"My foot is not fine," he said, adding: "I have pain in the foot, I cannot run in perfect conditions without [an injection]. But with the anaesthetic, I don't feel the pain."
The other semi-final sees Djokovic up against Tsonga, who hit back from two sets down to stun Roger Federer in the quarter-finals.
Federer is the only man to have beaten Djokovic this year, in a dramatic semi-final at Roland Garros earlier this month.
"It's not only the top four," said the 24-year-old Serbian. "There are other players that are able to play great tennis and Tsonga has proved it. It's all very close at this level, especially in the second week of a Grand Slam."
Asked about the propsect of becoming number one, he added: "My focus is to win every single match I play. I'm very close to reaching the number one but I try not to think about that too much."
Tsonga has much to be optimistic about with a 5-2 record against Djokovic, although he lost their biggest clash in his only Grand Slam final appearance at the 2008 Australian Open.
"I played against him many times," said the Frenchman. "He beat me in the big moments and I want to change that."