Carlos Moya is confident Rafael Nadal can continue to challenge for grand slams despite his advancing years.

After an injury-plagued 2016, Nadal's fortunes improved drastically this year, on Sunday adding the US Open title to his 10th French Open triumph to take his haul of majors to 16.

The 31-year-old has returned to the top of the world rankings and is just three grand slam triumphs away from matching Roger Federer's Open Era record of 19.

Moya, who has been part of Nadal's team since December and will take over the primary coaching responsibilities from the Spaniard's uncle Toni, suggested emulating Federer is a distinct possibility if his compatriot can stay fit.

"When I joined the team I knew that there was much more to come for Rafa, that if he stayed injury free and continued training with the same motivation, desire and confidence, that the tennis would come," former world number one Moya told the ATP Tour's official website.

"And in any case, we are talking about a legend, so the victories always come sooner or later.

"If he can stay as healthy as he is now, without injury, motivated, looking after himself the way he is, we will be talking about Rafa for years to come.

"He is a player who broke records as a teenager and who is now breaking them as a veteran as well. This is something we haven't see much in the history of tennis.

"People talk about how physical tennis is, but here he is at 31 winning two grand slams, right behind Federer. We mustn't underestimate his talent, his ability to improve, to analyse things. For me, there is no reason to think he can't spend many more years on Tour."

Nadal won his first grand slam - the 2005 French Open - just two days after turning 19, but Moya does not envision him running out of steam any time soon.

"Someone who has achieved so much will always find a new challenge. There aren't many challenges left, but there are some," said Moya.

"He is a very competitive person, a very demanding person and that helps a lot.

"He will keep finding motivation and his biggest motivation will be to keep improving, keep evolving, stay competitive and he knows that if he can do that, the options to win tournaments and fight at the top will be there."