Djokovic says he must buck up after another upset defeat

World No. 1 Novak Djokovic admitted he needs to work on his game ahead of next month's French Open after he was knocked out by Aslan Karatsev in the Serbia Open semi-finals yesterday morning (Singapore time).

The 28th-ranked Karatsev saved 23 of 28 break-points to advance to his second final of the year, following a 7-5, 4-6, 6-4 victory, gaining a measure of revenge for his defeat by Djokovic in the last four of the Australian Open.

It was a second surprise loss in as many weeks for Djokovic, who was also beaten in the last 16 of the Monte Carlo Masters by Britain's Dan Evans.

The 33-year-old is registered for the Madrid Open but did not confirm whether he would play at the May 2-9 Masters-level event, which will feature reigning French Open champion Rafael Nadal.

"Roland Garros is the main goal but I need to play better if I'm thinking about doing something there," said the 18-time Grand Slam champion.

"I have a lot of work ahead of me."

Djokovic commended the "bravery" of Karatsev and his "excellent play in the important moments" but revealed he felt "dizzy" in the third set. - AFP