11/11/2011 05:19 EST | Updated 01/11/2012 05:12 EST

No. 1 Novak Djokovic withdraws from Paris Masters because of shoulder injury; Tsonga advances

PARIS - Novak Djokovic has pulled out of the Paris Masters with a nagging shoulder injury before his quarterfinal against Jo-Wilfried Tsonga.

The top-ranked Serb announced on his official website on Friday he has "pushed himself to the limit" in the tournament, and that the injury got worse after his third-round comeback win against fellow Serb Viktor Troicki on Thursday.

Djokovic, the 2009 champion, made a string of unforced errors against Troicki, and was clearly impeded from playing his best tennis.

Tsonga, the 2008 champion, advances to the semifinals.