Rafael Nadal says his third-round win over Richard Gasquet was his best of this year's US Open as he works his way back after the abdominal tear that ended his Wimbledon campaign.

Prior to the US Open, Nadal had only played once since withdrawing from the Wimbledon semi-final against Nick Kyrgios in early July, losing to Borna Coric in Cincinnati.

The second seed got past Rinky Hijikata and Fabio Fognini in four sets in the first two rounds at Flushing Meadows before Saturday's 6-0 6-1 7-5 win over French veteran Richard Gasquet in two hours and 17 minutes.

"My best match in the tournament," Nadal told reporters. "Easy to say that because the other day was tough.

"But important improvement. But I need to keep going. It's a good victory for me. Straight sets for the first time. Third set had been a challenge. He increased the level.

"I went through some difficult moments. That's something that is good that I went through that and saved that moments with a positive feelings. Happy to be in the fourth round, without a doubt."

The victory over Gasquet meant he has progressed to the second week at Flushing Meadows for the 12th time in his career, although he conceded he would need to lift his level to take out the title, starting with Monday's fourth-round match with 22nd seed Frances Tiafoe.

Nadal is gunning for his third major title this calendar year in New York, having triumphed at the Australian Open and French Open.

The 36-year-old's Australian Open success in February came after minimal preparation due to a foot injury, similar to his US Open lead-up due to the abdominal issue.

"I think I played better in Australia than here going to the second week," Nadal said. "But I have zero background in terms of victories and all this stuff.

"Here I played little bit worse than in Australia, without a doubt. But the story of the year and the results on the slams have been incredible, so that helps.

"I don't know the balance, what's better or worse. But all these victories help to be a little bit more confident. It's a moment to increase, to making a step forward."

"Second week against a great player like Frances, I need to be ready to play and to raise my level. I hope to be able to make that happen.

"I know is the right moment to make an improvement if I want to keep having chances to keep going on the tournament."