Djokovic upbeat over top form

Serbia's Novak Djokovic in action during the fourth round match against Russia's Karen Khachanov. [Photo/Reuters]

Novak Djokovic is feeling more optimistic after continuing his fine run at Wimbledon by reaching the quarter-finals. The Serbian, seeded 12th at the All England Club, has dropped just one set on his way to a last-eight clash with Kei Nishikori. Djokovic cruised past Karen Khachanov 6-4 6-2 6-2 on Monday, marking the second straight major at which he has reached the quarter-finals. 

The 12-time grand slam champion, who has endured a difficult 12 months due to an elbow injury, said he was nearing his best form once more. 

"Approaching Roland Garros and Wimbledon this year for me is quite different from any other year because of circumstances that I was in in the last 12 months, the injury, the surgery, so forth," Djokovic said.