A defiant Rafael Nadal has warned his career is not over yet as he pledged that “sooner or later” he will be back at the very top of men’s tennis.

A tough 2015 has left many wondering whether the only thing left for the 29-year-old was retirement, but Nadal said on Sunday he was prepared to scrap his way back into contention.

Nadal has cut a doleful figure for much of the season but the fire was back in his eyes and the old snarl was on his face as he described how his mental composure was returning.

“In the US Open I did better, even if I lost the match (to Fabio Fognini in the round of 32). Tough loss, but I did better. Let’s try here to do better again,” Nadal, wearing a matador logo on his cap and T-shirt, said at the China Open.

“I think I am working well. I am very motivated to go for that challenge that brings me the chance to overcome a tough situation for me. I love that feeling, and I am going to fight to make that happen.”

Nadal has not got further than the quarter-finals in Grand Slams this year, even on his beloved Roland Garros clay, and he has slipped to seventh in the world from second a year ago.

But the Spaniard has confounded expectations more than once by rebounding from seemingly insurmountable injury problems to reclaim his place at tennis’s top table.

Now he said the old confidence was coming back and he pledged to use his final tournaments of the year as preparation for next season, which includes the Australian Open in January.

“It’s obvious that when you lose more than what you won, you lose your confidence, no? But the confidence comes back with victories and with good feelings on court,” he told reporters in Beijing.

“In the practices, there are better feelings for me. Now it remains to compete a little bit better (in matches). But I think it’s coming.”

The Spaniard said he was working on returning the old intensity to his ferocious forehand, but more importantly, he was again finding it easier to regulate his emotions on court.

“I was not able to control my emotions on court for a lot of months, so when that happens it’s almost impossible to play well, no?” he said.

“Last couple of months I’m feeling that I recovered that. I don’t feel that I am suffering on court as I did the first six, seven months of the season.

“So I try a little bit to play with calm. I believe that sooner or later I will be playing at a very high level again.”

First up for Nadal in Beijing will be Chinese wildcard Wu Di, as he looks to boost his 2015 return with a fourth title of the year.