Novak Djokovic, Roger Federer, Andy Murray and Stan Wawrinka can justify their status as Wimbledon's big four by making the semi-finals on Wednesday.

Defending champion, top seed and 2011 winner Djokovic takes on US Open champion Marin Cilic boasting a 12-0 career lead over the Croatian.

Seven-time champion Federer faces Gilles Simon with the Frenchman playing in his maiden Wimbledon quarter-final while 2013 winner Murray, seeded three, is up against surprise quarter-finalist Vasek Pospisil of Canada.

Fourth seed Wawrinka tackles 2007 semi-finalist Richard Gasquet, the second Frenchman in the last-eight.

Cilic, 26, lost to Djokovic in five sets in the quarter-finals in 2014 despite being two sets to one ahead.

He then went on to win a maiden Grand Slam title at the US Open in September.

"I know him very well. We played many, many matches on different surfaces," said Djokovic after reaching his seventh successive Wimbledon quarter-final and 25th in a row at the majors with a 6-7 (6/8), 6-7 (6/8), 6-1, 6-4, 7-5 win over Kevin Anderson of South Africa.

"I remember him mentioning earlier this year that he wants to focus mostly on Wimbledon, grass. That's where he feels like he has a best chance besides US Open. He's playing at a very high level."

Cilic admitted he needs to match Djokovic blow for blow on Wednesday.

"When Novak is playing at the speed that he's playing, I'm going to have to be more aggressive to play more risky tennis," said Cilic.

Federer, 33, is bidding to become the oldest Wimbledon champion and win a record eighth title.

The Swiss has been virtually untroubled on serve on his way to a 13th Wimbledon quarter-final, just one behind the record of 14 held by Jimmy Connors.

He has yet to drop serve, has faced just two break points in 58 service games and has committed only three double faults.

- Service king -

The last time he dropped serve was in the second set of his opening round win over Philipp Kohlschreiber in Halle -- more than 100 service games ago.

"Maybe the guys are returning terrible," joked Federer.

"Gilles Simon is one of the best return players we have in the game. I would think I'll be tested a lot. So that streak's maybe coming to an end, in my opinion."

Simon, one of three over-30s in the last eight, last made the quarter-finals of a Grand Slam in Australia in 2009.

He trails Federer 5-2 in career clashes. After winning their first two meetings in 2008, the Frenchman has lost five in succession although their only two Grand Slam matches -- at the 2011 Australian Open and 2013 French Open -- went to five sets.

Murray is into his eighth successive Wimbledon quarter-final and takes a 3-0 lead into his match-up with world number 56 Pospisil who had never previously got beyond the third round of a major before this Wimbledon.

All their three meetings have come in the last 10 months with the 25-year-old Canadian unable to win a single set.

Pospisil spent more than eight hours on court on Monday, first beating Viktor Troicki in the singles in five sets and then losing a five-setter with Jack Sock against Murray's brother Jamie and John Peers.

"He's played a lot of tennis here which is a positive for him," said Murray.

"But also maybe he's a little bit fatigued. So if that is the case, and I won't bank on that being the case, but if that is the case, I'll try to use that to my advantage."

Pospisil's win over Troicki was his third five-set win in four rounds at the All England Club this year.

French Open champion Wawrinka is in the quarter-finals for the second successive year and is bidding to become just the fifth man to win Roland Garros and Wimbledon in the same year.

Wawrinka, the only quarter-finalist not to have dropped a set at the tournament, faces 21st seed Gasquet with the two men locked at 1-1 in career meetings.

Gasquet won their first clash at the Paris Masters in 2006 with the 30-year-old Swiss gaining revenge at the 2013 French Open when he recovered from two sets to love down to win a fourth round encounter.
Source: AFP