World number three Rafael Nadal says he is battling issues with nerves, following a third-round exit at the Miami Open.
Nadal was beaten by fellow Spaniard Fernando Verdasco 6-4 2-6 6-3 at the ATP 1000 event in Florida, and could fall as low as seventh come the next release of the ATP rankings.
With another clay-court campaign on the horizon, the nine-time French Open winner says it is not the hard-court surface that has been his concern of late - but an issue mentally.
Nadal's season record fell to 15-5 after his loss to Verdasco and, while the 14-time grand slam winner feels he is improving, he concedes there is still work to do.
"It's not the question of tennis, [It's] the question of being relaxed enough to play well on court," Nadal is quoted as saying by ATPWorldTour.com.
"Today my game in general improved since a month and a half [ago]. But at the same time, [I'm] still playing with too many nerves for a lot of moments, in important moments."
Nadal said he could not put a timeframe on when he would overcome his struggles, but said he and his team would look to get him back on track.
"I have been able to control my emotions during 90 per cent, 95 per cent of my matches of my career... but I'm going to fix it," he said.
"I don't know if [I'll be better] in one week, in six months, or in one year, but I'm going to do it.
"It's something that I need to fix for myself and with my team.
"I need the help of my team, but especially I need the help of myself. That's what I am trying to do. Nobody's going to change the situation for you."
Nadal said he was looking forward to the return of the clay-court season, which begins in April.
"At this point in my career, I've won enough things to say I don't need to win more, but I want to do it," he said.
"I want to keep competing well. I want to keep having the feeling that I can be competing for every tournament I'm going to play, and I have the motivation to do it.
"Obviously clay is [a] surface that I've had some success, and I hope to be ready for it again."