Rafael Nadal is unsure just where his game is at, but insisted his wrist injury was having no impact at the US Open.

The Spanish fourth seed is yet to drop a set at Flushing Meadows, easing into the fourth round thanks to a 6-1 6-4 6-2 win over Russian Andrey Kuznetsov on Friday.

Nadal has been largely untroubled in his run to the last 16, but he is unclear as to just where he stands.

"I don't know in which kind of level I am. It's true that when I had to stop I was playing great. I felt myself ready for the French [Open]," he said.

"I don't know what could have happened at the French Open if I kept playing, but I felt ready.

"I don't know where I am today. Only thing I know is I am happy. I am excited to play the US Open.

"For me it's great news that I am on the tour again, and I am playing every day with less pain on the wrist. That's the most important thing."

Nadal said he could still feel his wrist injury, which sidelined him until the Rio Olympics, but played down its impact.

He said: "Still something, but something that is not limiting my game now. That's the most important thing."

For the first time at this year's tournament, 14-time grand-slam champion Nadal finished with more winners than unforced errors.

Nadal said his forehand, particularly down the line, was slowly getting back to its best ahead of a fourth-round meeting with Lucas Pouille.

"I am improving with that shot. Everybody knows that is a very important shot for me," he said.

"When I am able to play that shot well, then the court opens a lot, because then the cross-court forehand that I have a good one with topspin has a much better impact on the opponent.

"I did that well for a moments today. I need to keep doing it that way, improving a little bit every day."