World No 1 Rafael Nadal says "I'm going to play and try my best" ahead of his first match at the ATP Finals, which gets underway on Sunday - live on Sky Sports.
The top-seeded Spaniard pulled out of the Paris Masters last week with a right knee injury, casting major doubt over whether he would be fit for the season-ending finale at The O2 in London.
Nadal spoke to Sky Sports in an exclusive interview after arriving in London on Wednesday, when he insisted: "I've done everything I've needed to do to get ready for London."
He is guaranteed to end the year as No 1, irrespective of his performance at the finals, which begin on Sunday and end on November 19 - and you can watch every session live on Sky Sports.
And Nadal, who faces David Goffin of Belgium in the last of the first round of matches, remained adamant during a pre-tournament media conference that he will take to the court on Monday evening.
"If I didn't believe I could be ready for Monday I wouldn't be here," Nadal said. "I don't have to make a decision. I'm go to playing. That's my feeling today. I had problems in Paris a week ago. I go day by day, how I'm feeling.
"I cannot predict what will happen, but my feeling now is I'm going to play and try my best."
Nadal also insisted he had made no schedule demands on the organisers which would give him additional time to recuperate from his injury.
"I didn't have any request. I didn't ask anything," he said.
With last year's winner Andy Murray and runner-up Novak Djokovic absent through injury, there will be a new finals champion for the first time since 2011, when Roger Federer won the tournament for a sixth time.
Nadal, who won the French and US Opens earlier this year to take his Grand Slam tally to 16, has never won the year-ending event.
"It's always in my mind, during 13 years that I'm qualified," the 31-year-old said.
"Being here is an important thing, but for me the most important thing is the only thing that happened to me this year. Winning tournaments, competing every week, being healthy until Paris.
"I'm number one here, great. It's a very important achievement, especially at my age.
"It's something important for me, but that's all. It's going to be a nice moment when I receive Sunday the award, a year ago it was never in my mind to achieve that again.
"For me the most important thing is to finish the season well."
Federer opens on Sunday afternoon against Jack Sock of the United States, while third seed Alexander Zverev of Germany plays Marin Cilic of Croatia.
Austria's Dominic Thiem plays Grigor Dimitrov on Monday.