Novak Djokovic fell to Alexander Zverev in the 2020 Tokyo Olympics, but on Friday he got his revenge and is now a win away from history. In a thrilling five-set battle in Arthur Ashe Stadium, Djokovic defeated Zverev, 4-6, 6-2, 6-4, 4-6, 6-2, to reach the US Open final. Djokovic can reach No. 1 on the all-time Grand Slam trophy list and become the first calendar-year Grand Slam winner in 52 years with a win in the final. 

Zverev took the first set, 6-4, but Djokovic stormed back to win the second and third by scores of 6-2 and 6-4, respectively. That third set contained a historic 53-shot rally, the longest in US Open semifinals history and Djokovic's career. After the match, Djokovic said he was going through a "hurricane" or "tornado" during that 53-shot rally. 

With a strong 6-4 fourth set, Zverev forced a fifth to definitely decide who was going to the US Open final. An animated Djokovic withstood a valiant effort from Zverev to dominate that final set, 6-2, and punch his ticket. Djokovic is now 36-10 all-time in five-set matches and 7-3 overall against Zverev. 

"He's a great guy and an even better player," Djokovic said of Zverev. "I knew coming onto the court today it was going to be a great battle"

A win in Sunday's final would give Djokovic his 21st Grand Slam trophy, placing him ahead of Rafael Nadal and Roger Federer -- who both missed this year's US Open with injuries -- for the men's singles record. It would also be Djokovic's fourth US Open title. 

Zverev, who's still searching for his first Grand Slam title, had a shot at making a second consecutive US Open final after earning runner-up honors in last year's tournament. It took the first five-set tiebreaker in US Open final history to determine that match, as Dominic Thiem claimed a tightly-contested 2-6, 4-6, 6-4, 6-3, 7-6(6) victory. 

Djokovic owns an immaculate 27-0 major tournament record in 2021. Should Djokovic claim the US Open title, he'd be the first men's singles player since Rod Laver in 1969 to record a calendar-year Grand Slam. 

This wasn't the first time Djokovic and Zverev battled in a high-stakes match. Zverev, a 24-year-old German who came into Friday's match having won his last 16 matches, knocked Djokovic out of the 2020 Tokyo Olympics' semifinals. Zverev would eventually win Olympic gold. 

Earlier Friday, world No. 2 Daniil Medvedev advanced to the US Open final with a 6-4, 7-5, 6-2 victory over No. 12 seed Felix Auger-Aliassime. This will be his third career Grand Slam final and he's looking for his first win. 

The 25-year-old Russian will be a formidable challenger to Djokovic. He's dropped only one set this tournament and reached the 2019 US Open final, a match he fell to Rafael Nadal in. 

Medvedv has beaten Djokovic three times in ATP events. The pair also squared off in February's Australian Open, with Djokovic taking the title in a 7-5, 6-2, 6-2 victory. 

The US Open men's singles final is slated for 4 p.m. Eastern in Flushing, New York's Arthur Ashe Stadium.