Rafael Nadal says he is unsure if he will ever win another grand slam title following one of the worst years of his career.
The Spaniard has lifted 14 slams since turning professional in 2001, leaving him joint-second with Pete Sampras on the all-time list, three behind Roger Federer.
The 29-year-old has struggled for form and fitness since winning his ninth French Open in 2014 and doubts his chances of claiming a 15th major.
“I don’t know when that will happen and I don’t know if that’s going to happen,” he said following a coaching session in New Delhi, where he plans to open an academy for talented youngsters.
“The only thing I know is I’m working very hard to try to get the opportunities.”
Nadal relinquished his Roland Garros crown after bowing out in the quarter-finals this year, while he also suffered early exits at Wimbledon and the US Open, losing in the second and third round respectively.
Those results saw the former world number one slide to 10th in the rankings, but a late surge, including a run to the last four of the ATP World Tour Finals, enabled him to climb back up to fifth by the end of the year.
He is competing in the International Premier Tennis League as part of his preparations for the new season and, despite being disappointed with his performances in 2015, is confident that strong finish will stand him in good stead.
“2015 has been not the best season,” he said.
“(But) in the last three months, I finished much better and I’m happy the way I’m playing now.
“I need to keep going the same way that I finished the 2015 season.”