NEW YORK, Aug. 31 (Xinhua) -- Novak Djokovic battled past American Tennys Sandgren 6-1, 6-3, 6-7(2), 6-2 to reach the third round of the US Open on Thursday.

Djokovic has never lost before the third round of the US Open, and the Serbian has advanced to the semifinals or better in his past 10 appearances. He did not play at Flushing Meadows in 2017 due to a right elbow injury that kept him out after Wimbledon through the end of the season.

Djokovic is now 64-10 at the US Open, where he will next play No. 26 seed Richard Gasquet of France. The Serbian has won 12 of their past 13 meetings.

"We are working daily on trying to perfect the game and put it together. Obviously last couple months have been really, really good in terms of results," Djokovic said after the match. "That's what's exciting about this sport and about my game in general, the thing is that I still feel there are certain elements in my game that need some betterment. That's why you hit the practice courts daily and try to perfect the game."