The top three seeds progressed in the Paris Masters, although with varying degrees of comfort.
World number one Novak Djokovic had a hard time against fellow-Serbian Viktor Troicki, as he had to fight back to clinch a 4-6 6-3 6-1.
The top seed braved a shoulder injury to play, but struggled in the first set. The shoulder problem has troubled him of late, but he fought back in the second and cruised in the decider to set up a meeting with Jo-Wilfried Tsonga in the quarterfinals.
Afterwards, Djokovic revealed that he hadn't warmed up enough for the match, due to his shoulder problem.
At this level, everybody is equal, said Djokovic. I've known Viktor for a long time and there are no secrets.
I went on court not too warmed up or focused and I felt a little pain in my shoulder. I'm not really worried because I know it's not an injury, just strong inflammation.
Unfortunately I need couple of days to recover and I don't have that this week in Paris. I will have to find a way to recover and I'm sure I'll be fit for London.
Elsewhere, 16-time grand slam champion Roger Federer cruised past Frenchman Richard Gasquet with a 6-2 6-4 win.
The third seed secured an early break, against the local favourite, before getting a second break when Gasquet double-faulted at 2-4 down. He clinched the first set with an easy volley.
In the second, he broken again before clinching his very first match point to seal his progress to the quarterfinals.
Finally, World number three Andy Murray continued his impressive form with a 6-2 6-2 cruise against Andy Roddick.
The Scot was in violent form as he wrapped up the first 6-2 within just 31 minutes before easing through the second for his 27th win in 28 matches. He will now face fifth seed Tomas Berdych in the last-eights.
However, he did sustain a hamstring problem, and had to summon his trainer early in the first set.
I felt my hamstring, similar to last week, and I just wanted to get it checked out, said the 24-year-old.
I'll have to monitor it. Everyone has niggles at this stage of the season and you have to deal with them. I felt it early on, it might have been to do with the early start. Maybe I didn't warm up as well as I normally would.