PARIS - Novak Djokovic rallied from a set down to beat fellow Serb Viktor Troicki 4-6, 6-3, 6-1 and reach the Paris Masters quarter-finals on Thursday.
Andy Murray, Roger Federer, Tomas Berdych, David Ferrer of Spain and Jo-Wilfried Tsonga of France also advanced.
The top-ranked Djokovic looked a pale shadow of the player who dominated the first half of the season, making 44 unforced errors compared to 28 winners.
"It's obvious that I'm still not playing in the form that I had in the last 10 months," said Djokovic, who returned to action last week in Basel after a six-week injury layoff. "It takes a little bit of time to get into the rhythm."
Djokovic dropped serve twice to lose the first set to Troicki. But he broke for a 4-2 lead in the second, and levelled the match when Troicki sent a bakchand wide. The Wimbledon and U.S. Open champion then raced to a 4-0 lead in the final set.
Djokovic will next play Tsonga.
Murray routed Andy Roddick 6-2, 6-2 and will next face 2005 champion Berdych, who beat Janko Tipsarevic 7-5, 6-4.
The second-seeded Murray improved his record to 17-0 since the U.S. Open and has won 27 of his last 28 matches since mid-August.
Murray outclassed Roddick, hitting 27 winners compared to only four for the American. He broke Roddick twice in each set, taking the first with a crosscourt forehand winner before clinching victory with an ace.
"I started the match well, which against him is always important, because he plays his best when he's ahead," Murray said. "Because I broke him earlier, I was able to dictate a lot of what happened out there."
Roddick received a warning from the chair umpire at 2-0 in the second set after smashing his racket out of frustration.
Roddick will finish the season outside the top 10 for the first time since 2001.
"I just need to get in better shape as far as movement, and kind of catch up a little bit," Roddick said.
The fifth-seeded Berdych trailed 5-1 in the first set and 4-1 in the second, but fought back both times to clinch his spot in the eight-man ATP World Tour Finals. His victory meant Tsonga and Mardy Fish also secured spots in the season-ending tournament in London, with Tipsarevic missing out.
Tipsarevic made two double-faults in a row to set up match point for Berdych.
Federer downed Richard Gasquet of France 6-2, 6-4 to next meet Juan Monaco of Argentina.
The third-seeded Swiss broke serve twice in the first set and took a 4-3 lead in the second on a double-fault from Gasquet before clinching victory with a forehand winner.
Meanwhile, fourth-seeded Ferrer ousted Alexandr Dolgopolov of Ukraine 6-3, 6-2, and the sixth-seeded Tsonga defeated Andreas Seppi of Italy 6-3, 6-4.
Ferrer will take on American John Isner, who beat Feliciano Lopez of Spain 6-4, 6-2.
A double-fault from Seppi gave Tsonga a 2-0 lead and the Frenchman took the first set with a forehand winner. The 2008 champion then broke for a 4-3 lead in the second, winning the match when Seppi netted a forehand.
Fish was leading 6-1, 6-7 (6), 2-1 against Monaco when a left hamstring injury forced him to retire.
Fish received treatment in the final set but was forced to quit after playing one more point.
"I started feeling it probably late in the second set," Fish said. "It went from sort of tightness and an uncomfortable feeling to, in that last game that I served, a lot more pain, a lot sharper."
The injury was a recurrence of his hamstring problem from the Swiss Indoors in Basel last week, but Fish still plans to play in the tour finals in London.