Novak Djokovic said his rivalry with Carlos Alcaraz was becoming like the one he shared with the Spaniard's compatriot, Rafael Nadal, after needing nearly four hours to outlast the 20-year-old world No 1 in an epic Cincinnati Open final on Sunday.

In a thrilling rematch of their Wimbledon showdown, Djokovic saved a match point before avenging his defeat with a 5-7 7-6(7) 7-6(4) triumph in three hours and 49 minutes - the longest best-of-three sets final in ATP tour history.

The seasoned Serbian compared it with the 2012 Australian Open final, when he defeated Nadal in five hours and 53 minutes. The pair shared a storied rivalry over the last 15 years and faced each other 59 times.

"I don't think I've played too many matches like this in my life," Djokovic, 36, told reporters. "Maybe I can compare it to the final against Nadal at the 2012 Australian Open.

"Obviously, three sets today, but almost four hours. You just have to put your hats down to a guy like that. He plays so maturely, handles the pressure so well for a 20-year-old.

"We cannot forget how young he is. That's something that is so impressive about him."

Sunday's meeting was the fourth one between Djokovic and Alcaraz, with each player having won two matches. Djokovic beat Alcaraz in the French Open semifinals, and the Spaniard earned his revenge in a memorable five-set Wimbledon final.

"The feeling that I have on the court reminds me a little bit when I was facing Nadal when we were at our prime," added Djokovic, who moved ahead of the Spaniard in the all-time men's majors list after winning his 23rd crown at Roland Garros.

"Each point is a hustle. Each point is a battle. You've got to basically earn every single point, every single shot, regardless of the conditions. It's amazing to be able to experience that with him on the court."

Up next for both players is the US Open, where Alcaraz will defend his title when the tournament starts on August 28.

"It's great to hear those things from Novak, (who) has played iconic matches, storied matches," Alcaraz said. "That means the team and myself, we are doing great work, we are on a good path."