Novak Djokovic of Serbia returns a shot during his men's singles tennis match against Fabio Fognini of Italy at the Shanghai Masters tennis tournament, Oct 10, 2013. [Photo/Agencies]

Defending champion and top seed Djokovic survived a scare against flamboyant Frenchman Gael Monfils to reach the semifinals.

The 26-year-old Djokovic defeated Monfils 6-7(4), 6-2, 6-4 and fired four aces during the match, which lasted two hours and 23 minutes. He won 80 percent of first serve points.

"It was a tough match today, a tough battle," said Monfils. "I'm still happy. I haven't practiced much before here. To come here (and play) strong was good. He is one of the best players in the world, and I have no shame today... I'm already looking forward for 2014."

Tsonga moved to within 135 points of eighth placed Roger Federer in the ATP Race To London after the Frenchman advanced to the semifinals with a 6-2, 6-3 win over German Florian Mayer in 65 minutes.

Gael Monfils of France receives medical treatment during his men's singles tennis match against Novak Djokovic of Serbia at the Shanghai Masters tennis tournament in Shanghai, Oct 11, 2013. [Photo/Agencies]