The Paris Masters was hit with a double setback as both Rafael Nadal and Roger Federer withdrew because of injury.
Second seed Federer, who was due to play James Blake in the evening in the third of the day's quarter-finals, was the first to pull out citing a back injury.
Organisers would have then looked on in horror as Nadal, the top seed, called in his trainer when 4-1 down to Nikolay Davydenko in his last-eight match. The Spaniard attempted to play on but after losing the next two games, and therefore the set, to his Russian opponent, he chose to quit. Nadal later admitted he had been hampered by a knee injury.
It means 11th seed Blake advances through to the semi-finals where he will play Jo-Wilfried Tsonga, who came from behind to beat Andy Roddick 5-7 6-4 7-6 (7/3) in the evening match.
Davydenko, the sixth seed, will take on David Nalbandian in the first semi-final on Saturday after the Argentinian ousted Andy Murray in a high-quality match on Centre Court first up on Friday.
Federer announced he was pulling out to avoid aggravating a back injury he first suffered during his second-round victory over Robin Soderling.
"My back has been stiff for the last few days," he said.
"The treatment I had last night (Thursday) didn't do anything. So on precaution and because I cannot be at 100%, I've taken the difficult decision not to play."