Novak Djokovic moved within two wins of an historic calendar Grand Slam at the US Open after completing a merciless comeback against Matteo Berrettini 5-7 6-2 6-2 6-3 en route to the semi-finals.

Berrettini was seeking revenge for his Wimbledon final loss to Djokovic and the Italian sixth seed gave himself a good chance after winning the opening set at Flushing Meadows on Wednesday.

But Berrettini was helplessly outclassed in a devastating display from world number one Djokovic, who is bidding to become just the third man to sweep all four majors in a year and first since 1969.

The 20-time major champion, who can also break the record for most men's slam titles – currently tied with Rafael Nadal and Roger Federer, will face Alexander Zverev in the New York semis.

For the third consecutive match, Djokovic done it the hard way, rallying after dropping the opening set, just like he did against Jenson Brooksby and Kei Nishikori.

In a brutal display of big hitting, Berrettini had the crowd roaring – firing down seven aces and saving two break points in a marathon first set lasting one hour, 17 minutes.

Berrettini held serve in a physically demanding sixth game after 12 minutes and seven deuces.

Djokovic – not without his chances – did not look like his usual self, spraying a forehand wide as Berrettini seized control following four set points.

Berrettini was looking to claim his first win over Djokovic after three consecutive defeats and earn his first top-10 victory at a grand slam (0-5 heading into the contest), but the Serb star turned the match on its head into the second set.

Djokovic, though, flipped the switch as he broke for the first time to move 3-1 ahead before consolidating for a 4-1 lead, silencing the pro-Berrettini crowd in New York, where the latter was unable to stop the rot.

Berrettini looked deflated and tired in the third set – Djokovic racing out to a commanding 3-0 advantage.

Djokovic missed the chance to move 5-2 ahead but it only delayed the inevitable as he fended off a break point the very next game to eventually earn a two-sets-to-one lead.

And the 34-year-old could not be stopped as he celebrated his 80th US Open match win in emphatic fashion.

Data slam: Can Djokovic be stopped?

Djokovic extended his winning streak at grand slams to 26 matches, while he also remains unbeaten in US Open quarter-finals (12-0). The record-chasing star also owns a 9-0 major record in 2021 after dropping the first set.

WINNERS/UNFORCED ERRORS

Djokovic – 44/28
Berrettini – 42/43

ACES/DOUBLE FAULTS

Djokovic – 12/4
Berrettini – 17/2

BREAK POINTS WON

Djokovic – 5/16
Berrettini – 1/5