World No 1. Novak Djokovic saved two match points to prevail 4-6, 7-6(6), 6-4 over Juan Martin Del Potro here early Saturday to advance to the semifinals of the Italian Open, where the Serb will face Diego Schwartzman.

Djokovic, a four-time winner in Rome, needed three hours and one minute to dispatch the Argentine, who delivered one of his most impressive performances in recent years.

It was only the seventh match of the season for Del Potro, who ended up needing more time than expected to recover from a knee injury, but he showed no signs of rust in the clash on center court at the Foro Italico.

"I'm so happy you come back," the Serbian told Del Potro at the end of the epic encounter.

Del Potro, ranked ninth in the world, powered through the first set with drives clocked at 130km/h (80mph).

Djokovic's first service break came only in the sixth game of the second set. He pulled ahead 5-3 only to be broken in the ninth game and find himself trailing 6-4.

Yet the Argentine failed to execute on successive match points and Djokovic went on to win the tiebreaker and force a third set. The Serb took control with a break in the fifth game and the contest concluded at 1.05 am.

"I never lost faith I could come back to the match. One break of serve, mini break in the tie-break when he was 6/4, more or less open forehand that he was making the entire match, that's all it took for me to come back," Djokovic said afterward.

"(Del Potro) missed a couple crucial points in the tie-break. Also break point third set, quite easy forehand. That's what happens. That's sport. I'm just really pleased to overcome," the Serbian said.

Looking back at the first set, Djokovic said that the Argentine "was playing really well, gave me a lot of trouble."

Next up for Djokovic is Argentina's Schwartzman, who cruised to a 6-4, 6-1 victory Friday over Kei Nishikori of Japan.

The Serbian has triumphed in both of his previous encounters with Schwartzman: at the US Open in 2014 and the French Open in 2017.

Spain's Rafael Nadal got past countryman Fernando Verdasco 6-4, 6-0 on Friday to book a spot in the semifinals against Greece's Stefanos Tsitsipas.

Nadal, the world No. 2, lost to the 20-year-old Tsitsipas last week in the semifinals of the Madrid Open.