Rafael Nadal has cast more doubt on the prospect of him defending his US Open title by confirming he plans to play in the Madrid Open - which starts a day after the Grand Slam concludes.

The tournament will be played from 31 August to 13 September this year as part of a revised ATP calendar.

"Rafa has confirmed his participation in Madrid," said tournament director Feliciano Lopez.

Nadal responded to the Twitter post from his long-time Davis Cup team-mate by replying: "See you in Madrid in September."

Last month, the world number two said he had little desire to travel to Flushing Meadows at that time.

Nadal's exhilarating five-set win over Russia's Daniil Medvedev in last year's US Open final put him within one of Roger Federer's record of 20 Grand Slam titles.

Nadal has won 12 of his 19 majors at the French Open, which is set to take place at Roland Garros on 27 September.

Swiss Federer, 38, will miss the rest of the 2020 season after knee surgery earlier this year.

Serbia's 17-time major champion Novak Djokovic, who had toned down initial scepticism about the US Open before testing positive for coronavirus, has not yet committed.

Six-time women's champion Serena Williams has confirmed she will play at Flushing Meadows.

The professional tours are set to resume early next month after being suspended since March because of the coronavirus pandemic.