Shanghai - Jo-Wilfried Tsonga claimed his third revenge win in two months over Novak Djokovic as he produced a 1-6, 7-5, 6-1 Gold group comeback to spoil the Serbs hopes for a perfect record on Thursday at the Masters Cup.

The 23-year-old Tsonga is out of consideration for a semi-final spot, but earned a moral victory over the man who beat him in the Australian Open final in January. Djokovic ended with a 2-1 mark.

"It's just very good to have a year like this," said the Frenchman. "With all my problem (knee surgery) I played very well. I'm very happy for this year."

Tsonga has now proved his point over the world number three in the Bangkok final and third round at Paris Bercy in addition to the year-end spectacular.

Russia's Nikolay Davydenko joined Djokovic into Saturday's semi- finals later Thursday with a swift 6-3, 6-2 win over rising Juan del Petro of Argentina.

Djokovic and Davydenko finished the group with 2-1 records while Tsonga and del Potro went out on 1-2 each.

Andy Murray of Britain is also assured of a semi-final berth from the other group, with the remaining berth to be decided on Friday between holder Roger Federer and Frenchman Gilles Simon. Federer must beat Murray while Simon plays Czech alternate Radek Stepanek.

Tsonga was competing purely for pride on Thursday and showed that he is a force to reckoned with when he rallied after a first-set thrashing at the hands of the world number three.

"He was better than me in the two first sets, but I take the second one. It was maybe difficult to stay very concentrated because he's qualified and he has to look to the next match."

Djokovic heads into the weekend with confidence still intact after losing all three of his matches a year ago on his debut.

"I feel happy because I am through to the semi-final, which was main goal," he said.

"I took every match seriously and wanted to win this one. But he played well in the third set and I had some unforced errors. But the important thing is that I'm through. It's not the end and I think I have enough quality to go further."

Tsonga finished his job in one hour, 38 minutes with a winning lob which the Serb could only watch sail over his head.

Djokovic has won three quality titles in 2008, the first Grand Slam of the season and Masters events in Indian Wells and Rome, but has not tasted trophy success since May.

Tsonga improved to 3-1 over his rival and leaves Shanghai primed to lift his number seven ranking when he resumes again in January. (dpa)