Sept. 10 (UPI) -- Novak Djokovic is two wins from a rare calendar-year Grand Slam. Alexander Zverev, who denied Djokovic of a Golden Slam this summer in Tokyo, stands in his way.
The foes, both in the Top 5 in the world, face off Friday in the U.S. Open semifinals. The match, which airs on ESPN, is expected to start about 7 p.m. EDT in Forest Hills, N.Y.
"I know it's going to be a battle," Djokovic told reporters Wednesday. "I'm ready for it. These are the hurdles I need to overcome to get to the desired destination.
"The result is something I can't predict, but I can put myself in the best possible state of mind and body to perform as well as I can."
Djokovic, ranked No. 1, is 6-3 in career matches against Zverev. The Serbian is 2-0 against the German in Grand Slam meetings.
He can become just sixth player in history to win a calendar-year Grand Slam, joining Rod Laver, Don Budge, Maureen Connolly, Margaret Court and Steffi Graf.
Zverev rallied from a first-set loss to upstage Djokovic in three sets in the semifinals at the 2020 Summer Games. The No. 4 player in the ATP rankings could deny Djokovic of making history for the second time in three months with a win Friday.
"Against him, you prepare that you have to play the best match you can," Zverev told reporters Wednesday. "You have to be perfect, otherwise you will not win.
"Most of the time you can't be perfect, that's why most people lose to him."
The winner of the Djokovic-Zverev match battles the winner of the other men's semifinal. No. 2 Daniil Medvedev of Russia faces No. 15 Felix Auger-Aliassime for the first finals spot at 3 p.m. EDT Friday at the USTA Billie Jean King National Tennis Center.
Djokovic opened as the favorite for the hard-court Grand Slam and is expected to dispatch of Zverev, who is known for a powerful serve and masterful backhand.
"Against him you have to win the match yourself you have to dominate the points and do it with very little unforced errors," Zverev said of Djokovic.
Zverev uses his 6-foot-6 frame to blast serves, which force awkward returns. He snipes his returns into hard-to-reach areas of the court with regularity and uses long rallies to tire opponents.
Djokovic, who stands at 6-foot-2, has one of the most well-rounded skill sets in the history of the sport.
The 20-time Grand Slam champion is arguably the best returner of all time. He uses flexibility, strength and focus to field balls that many players could not reach. His overall consistency, movement and endurance often frustrates opponents.
"I know what my strengths are and I stick to them," Djokovic said. "I've worked over the years to perfect my game so my game can have literally no flaws.
"I want my opponents to feel that I can get any ball."
Djokovic, 34, admitted that his game "fell apart" in the Olympic semifinals. He said he doubted his shots and Zverev was able to read his serve.
"He won it comfortably in the end," Djokovic said. "He deserved to win a gold medal. ... He is in fantastic form and in the best form next to Medvedev."
Zverev, 24, is undefeated since his gold medal victory in Tokyo. His 16-consecutive match wins included his Olympic run and a title last month at the Western & Southern Open in Cincinnati.
He beat Spain's Albert Ramos-Vinolas, Italy's Jannik Sinner and Americans Jack Sock and Sam Querrey in his first four matches in Forest Hills. He edged Lloyd Harris of South Africa in straight sets in the quarterfinals.
Djokovic beat Holger Rune of Denmark in the first round. He also beat Tallon Griekspoor of the Netherlands, Kei Nishikori of Japan and American Jenson Brooksby in his next three U.S. Open matches. Djokovic beat No. 8 Matteo Berrettini of Italy in four sets Wednesday in the quarterfinals.
Zverev is 0-2 in his only two Grand Slam semifinal appearances, the 2020 Australian Open and the 2021 French Open.
Djokovic said he knows Zverev's game "very well," but the match could be determined in a variety of ways based on nerves, mistakes and other factors. He also said overthinking about his run at history can be a "burden."
"Of course I'm aware of the history and I'm aware of the motivation," Djokovic said. "If I start to think about it too much, it burdens me. I want to really go back to the basics of what works for me mentally.
"I'm in a position that is very unique. I'm very grateful for that and inspired to play my best tennis. I know what works for me to win just the next match."