Sharjah24 - AFP: After his chances of winning the first-ever ATP Finals title and finishing the year as the top-ranked player were all but dashed on Tuesday, Rafael Nadal said he was "going to die" attempting to go back to the level of tennis that saw him win a record 22 Grand Slam singles titles.

The 36-year-old Spaniard was speaking after a 6-3, 6-4 loss to Canada's Felix Auger-Aliassime in Turin.

Nadal has lost both his matches in Turin -- he fell to Taylor Fritz on Sunday -- and will need to win his last Green Group match against Casper Ruud to keep alive his chances.

Even then it might be out of his hands.

Ruud -- who beat Auger-Aliassime in their opening clash -- faces Taylor Fritz later on Tuesday and according to the ATP needs just to win a set in that match to eliminate Nadal.

That would confirm Nadal's teenage compatriot, US Open champion Carlos Alcaraz, as year-ending world number one.

"I mean, I don't think I forget how to play tennis, how to be strong enough mentally," said Nadal, who was playing in just his third singles match since the US Open in September.

"I just need to recover all these positive feelings and all this confidence and all this strong mentality that I need to be at the level that I want to be.

"And I don't know if I am going to reach that level again. But what I don't have any doubt, that I going to die for it."

Nadal -- who has nevertheless won the Australian Open and French Open this year -- praised 19-year-old Alcaraz, who is not able to play in Turin due to an abdominal injury.

"Just well done for Carlos in this case," said Nadal.

"Happy for him. Big achievement for him. Well done. Great news for our sport in Spain. He deserved it after a great season."