SHANGHAI -- Novak Djokovic made a comeback 6-7 (4), 6-1, 6-4 victory over the Czech Republic's Jakub Mensik to advance to the semifinals of the ATP Shanghai Masters on Friday.

In the closely contested first set, the Serbian initially took the lead in the tiebreak, but was pegged back and bested by the 19-year-old. However, the veteran found his momentum in the second set by breaking serves twice in the second and sixth game. Though the Czech fought back with a break in the third set, he could not stop Djokovic from pursuing his 100th Tour-level win.

"China has been always a happy place, a place where I really played my best tennis throughout my career. These kinds of matches against teenagers, it's something that really motivates and pushes me to really dig deep," said Djokovic.

He also paid tribute to Rafael Nadal, who announced his retirement on Thursday. "I have lots of respect for him and the legacy that he has created. He remains the greatest rival that I ever had. He has impacted me a lot as a player in my development. He can be extremely proud of his achievements and the mark that he left not only in this sport of tennis, but also sport in general," he said.

Elsewhere, America's Taylor Fritz cruised into the last four by easing past David Goffin of Belgium 6-3, 6-4.

"I played a really good match. Played aggressive, took my chances. I think my serve's always been a huge part of my game. Especially in the second set of this match, I feel like I'm serving a good percentage and hitting spots very well," said Fritz.

Now facing Djokovic in the semifinals, Fritz said he was hopeful of his prospects. "We played a lot of times, and I've never [beaten] him, so I'm really waiting for that. Maybe I can get a first win on him," the American said.

In the men's doubles, Nikola Mektic of Croatia and the Netherlands' Wesley Koolhof defeated Edouard Roger-Vasselin of France and Mexico's Santiago Gonzalez 6-7 (3), 6-4, 10-6 to reach the final.