Rafael Nadal has admitted that the 2015 season was his worst thus far in his career and revealed that he had too much "anxiety" and could not "control the pressure".

The Spaniard is coming into the 2017 campaign on the back of two injury plagued seasons, which has seen him win just five titles in the last two years. Nadal had earlier admitted that the 2015 campaign was more of a "mental struggle" rather than a physical one, which he admits forced him to question himself with regards to the reasons for his lack of competitiveness.

The 14-time Grand Slam winner looked like he was returning to his best at the start of 2016 when he won back-to-back titles in Barcelona and Monte Carlo, but a wrist injury at Roland Garros disrupted his season. He returned in the latter stages of the season, but was unable to recapture his form that eventually saw him cut his season short in October after his loss at the Shanghai Masters.

Nadal returned at the start of the year at the Brisbane International where he lost in the quarter-finals to world number three Milos Raonic. However, his best performance in recent years came at the 2017 Australian Open where he beat higher ranked players to make the finals, only to lose to long-time rival and friend Roger Federer in a gruelling five-set encounter.

"I had much anxiety and couldn't control the pressure," Nadal said as quoted by tennisworldusa.org. "It's difficult to explain these things. I came back home and said myself: you won almost everything, why are you nervous? I asked myself this question every day. The competition kills you. I never thought about calling it a career, but take a few months off yes."

"Now I am very willing to play, I started well the year competing against the best players in the World and having chances to win. If I keep working this way, I can have a good season.

"I was happy because I did some important steps forward. Federer played better than me and I think he deserved to win. He was very inspired, played very aggressive and there were not many long points. I had some emotional weeks where I enjoyed myself. In the semifinals I thought: if I lose it's because he deserved to win, but I am enjoying. It was something special," the Spaniard added.