Rafael Nadal optimistic despite loss

Rafael Nadal was stunned in a 6-1, 2-6, 6-4, 3-6, 7-6 (8-6) defeat to Frenchman Lucas Pouille at the US Open on Sunday.

RafaelNadal - Cropped

For the first time since 2004, Rafael Nadal failed to reach the quarterfinals of a grand slam in a calendar year – with his run at New York his best.

Rafael Nadal insists he is still capable of challenging for grand slams despite his surprise fourth round loss to Lucas Pouille at the US Open.

Read: >Lucas Pouille stuns Rafael Nadal at US Open

The Spanish fourth seed was stunned in a 6-1, 2-6, 6-4, 3-6, 7-6 (8-6) defeat to Frenchman Pouille at Arthur Ashe Stadium on Sunday.

For the first time since 2004, Nadal failed to reach the quarterfinals of a grand slam in a calendar year – with his run at New York his best.

But the 30-year-old believes he knows what he needs to work on, saying: "You can see it or you can write the way that you want. I know what's going on. I know what I have to do."

"When you are able to play semifinals of Masters 1000s, winning tournaments like Barcelona, playing good tournaments in the other events, it's not a question of level to be in the final rounds of the grand slams.

"It's just a couple of things that for some reasons didn't happen, and you need to be ready to have the auto-critic. You need to be auto-critic.

"It's something that I believe is really going to change."

While Nadal paid tribute to Pouille, the 14-time grand-slam champion did have his chances – leading 4-2 in the fifth set.

He also sent a short forehand into the net at 6-6 in the tie-break, but denied pressure was the reason.

"After winning 14 [grand slams] and being in semifinals a lot of times, you feel that's pressure?" Nadal asked.

"I'm 30-years-old, after having the career that I have had, it's not a question of pressure."