World number one Rafael Nadal has revealed how his injury problems in 2014 caused anxiety and impacted his performance on the court, leaving a three-year gap in his next Grand Slam win.

The Spaniard began 2014 by losing the Australian Open final to Stan Wawrinka owing to a back problem, which later required stem cell treatment.

Nadal was able to bounce back by winning his ninth French Open title later that year, but missed the hard-court season after an injury to his right wrist.

He then had to end his season early in October 2014 to undergo an appendix removal surgery.

The 31-year-old returned in 2015 only to win just three titles, none of which were Masters or Grand Slams. He reached the quarterfinals of the Australian Open and the French Open, but was eliminated early on at Wimbledon and the US Open as he fell to number five in the ATP tennis rankings that year.

"In 2014, I linked several injuries and health problems, all of which caused 2015 to start with doubts," Nadal told El Mundo via Express, recalling the struggle.

"And those doubts produced an anxiety that was unknown to me until then, the reality being that this internal stress lasted for six or seven months."

"I have not had them again, they have disappeared, what can they come back to? It is possible."

Nadal has since turned his career around with a resurgence in 2017, winning six titles, including the French Open and Australian Open, ending the year as the top-ranked player in tennis, despite a recent knee injury at the ATP Finals in London.

He added that any goal can be achieved if one tries hard and that even with uncontrollable factors, he will always give his all.

"No one fails if he does his best to win, he fails when he does not try hard enough to achieve his goals," he said.

"Everything possible is done to win, but there are uncontrollable factors, that for me is not to fail, I have never let myself go in games or in training."