British number one Andy Murray plays Canadian Vasek Pospisil, who has already knocked out one Briton - James Ward - and returns to Centre Court, where he won the men's doubles title last year.
Defending champion Novak Djokovic, meanwhile, faces US Open champion Marin Cilic after surviving a huge scare against Kevin Anderson to reach his 25th successive Grand Slam quarter-final.
Seven-time champion Roger Federer plays 12th seed Gilles Simon of France while French Open winner Stan Wawrinka takes on Richard Gasquet in a match dubbed 'the battle of the backhands'.
What to look out for on day nine
Murray - the last remaining Briton in the singles - takes on world number 56 Pospisil in the first match on Centre Court.
Having never been past the third round at a Grand Slam before, 25-year-old Pospisil is in uncharted territory.
He has played three five-set matches so far in the singles and another gruelling five-setter in the doubles against Andy's brother Jamie, which meant he spent a total of eight hours on court on Monday alone.
Murray, 28, fully intends to take advantage of any signs of tiredness.
"He might be a little bit fatigued, but then again he's played so much tennis that he's going to be comfortable in the conditions and in a good rhythm," said the 2013 champion.
"If he is tired I'll obviously try to capitalise on that, but I won't bank on it."
Gilles Simon will be facing Roger Federer today.
