New Delhi: Rafael Nadal cast doubt Thursday on whether he could win another Grand Slam after his long reign as French Open champion ended in 2015 and his rankings slid during the worst year of his career. The 29-year-old Spaniard said he was working hard to return to form and was happy with the way the year ended after a resurgence at the World Tour finals in London in November.


Rafael Nadal. Pic/PTI

But asked whether he could clinch another major title to add to the 14 Grand Slams he has already accumulated, Nadal was unconvinced when speaking to reporters in New Delhi. "I don't know when that will happen and I don't know if that's going to happen," he said.