|After a superb start to the season Djokovic has to battle hard to defeat Serbia's Viktor Troicki [AFP]
Novak Djokovic rallied from a set down on Thursday to beat fellow Serb Viktor Troicki 4-6, 6-3, 6-1 and reach the quarterfinals of the Paris Masters.
Andy Murray of Britain, Tomas Berdych of the Czech Republic, 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 the court in Basel last week 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. But he broke for a 4-2 lead in the second, and levelled the match when Tipsarevic sent a backhand 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 of the United States 6-2, 6-2 and will next face 2005 champion Berdych, who beat Janko Tipsarevic 7-5, 6-4.
The second-seeded British player improved his record to 17-0 since the U.S. Open and has now 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."
"I just need to get in better shape as far as movement, and kind of catch up a little bit"
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 at the ATP World Tour Finals. His victory meant Tsonga and Mardy Fish also secured spots at the season-ending tournament in London, with Tipsarevic missing out (see full list below).
Tipsarevic made two double-faults in a row to set up match point for Berdych.
Meanwhile, fourth-seeded David Ferrer of Spain ousted Alexandr Dolgopolov of Ukraine 6-3, 6-2, and the sixth-seeded Tsonga defeated Andreas Seppi of Italy 6-3, 6-4.
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.
ATP WORLD TOUR FINALISTS:
1. Novak Djokovic (Serbia)
2. Rafael Nadal (Spain)
3. Andy Murray (Great Britain)
4. Roger Federer (Switzerland)
5. David Ferrer (Spain)
6. Tomas Berdych (Czech Republic)
7. Jo-Wilfried Tsonga (France)
8. Mardy Fish (United States)