Novak Djokovic’s quest for the first men’s singles Calendar Grand Slam in 52 years and record-breaking 21st Major reaches its penultimate hurdle on Friday in a US Open.

But his semi-final showdown is toughest test so far, a rematch Tokyo Olympic champion Alexander Zverev. It was German fourth seed Zverev who ended top-ranked Djokovic’s bid for a Golden Slam with a fightback July semi-final triumph in Tokyo. Both men are girding for an epic rematch at Arthur Ashe Stadium as history looms for men’s tennis.

Djokovic is 6-3 against Zverev, who is on a 16-match win streak while Djokovic has won 26 straight Slam matches.

HEAD TO HEAD

Djokovic leads 6-3

2017 Rome Clay F Zverev 6-4, 6-3

2018 Shanghai Hard SF Djokovic 6-2, 6-1

2018 ATP Finals Hard RR Djokovic 6-4, 6-1

2018 ATP Finals Hard F Zverev 6-4, 6-3

2019 French Open Clay QF Djokovic 7-5, 6-2, 6-2

2020 ATP Finals Hard RR Djokovic 6-3, 7-6 (7/4)

2021 ATP Cup Hard RR Djokovic 6-7 (3/7), 6-2, 7-5

2021 Australian Open Hard QF Djokovic 6-7 (6/8), 6-2, 6-4, 7-6 (8/6)

2021 Olympics Hard SF Zverev 1-6, 6-3, 6-1

Medvedev leads 1-0

2018 Toronto Hard R32 Medvedev 3-6, 6-4, 7-6 (9/7)

Second seed Daniil Medvedev, a finalist here in 2019, takes on first-time semi-finalist and 12th seed Felix Auger-Aliassime in the other semi-final.

“You have to be perfect, otherwise you will not win,” Zverev said. “Most of the time you can’t be perfect. That’s why most of the time people lose to him.”

Djokovic is expecting Zverev’s best.

“I know it’s going to be battle,” Djokovic said. “But I’m ready for it. These are the hurdles I need to overcome in order to get to the desired destination.”

Djokovic is trying to be the first man to sweep the major crowns in the same year since Rod Laver in 1969. The 34-year-old Serbian seeks his fourth US Open title and 21st career Slam trophy, which would give him the men’s record total he currently shares with Rafael Nadal and Roger Federer, both absent due to injuries, outright.

“I’m aware of the history. Of course it gives me motivation,” Djokovic said.

“If I start to think about it too much, it burdens me mentally. I want to really go back to the basics and what really works for me mentally. I’m in a position that’s very unique. I’m very grateful for that. I’m inspired to play my best tennis.

“I know a lot of people want to hear me talking about it. But let’s talk about it hopefully on Sunday.”

Zverev, last year’s US Open runner-up, needs to get past Djokovic to have a chance at his first Grand Slam title. The world No 1 is ready for a marathon fight with his younger rival.

“He’s in a fantastic form. Next to Medvedev best form,” Djokovic said. “Physically I feel as fit as anybody out there. So I can go the distance. I’m going to be ready to go five sets, five hours, whatever it takes. That’s why I’m here.”

Auger-Aliassime will play in his first Slam semi-final when he meets Medvedev.

“I need to step up and be confident,” the Canadian said. “I need to try to put pressure on him. But it’s going to be tough. I need to be ready for his best.”

Medvedev, who lost to Djokovic in this year’s Australian Open final and to Nadal in the 2019 final in New York, seeks his first Slam crown.

“I have this experience. I’m not going to be tight,” he said. “If I play good, it’s going to be not easy for my opponent.”

The two have played each other only once before and Medvedev leads 1-0

Paths to the semi-finals (x denotes seed):

Novak Djokovic (SRB x1)

RD128: bt Holger Rune (DEN) 6-1, 6-7 (5/7), 6-2, 6-1

RD64: bt Tallon Griekspoor (NED) 6-2, 6-3, 6-2

RD32: bt Kei Nishikori (JPN) 6-7 (4/7), 6-3, 6-3, 6-2

RD16: bt Jenson Brooksby (USA) 1-6, 6-3, 6-2, 6-2

QF: bt Matteo Berrettini (ITA x6) 5-7, 6-2, 6-2, 6-3

Alexander Zverev (GER x4)

RD128: bt Sam Querrey (USA) 6-4, 7-5, 6-2

RD64: bt Albert Ramos-Vinolas (ESP) 6-1, 6-0, 6-3

RD32: bt Jack Sock (USA) 3-6, 6-2, 6-3, 2-1, retired

RD16: bt Jannik Sinner (ITA x13) 6-4, 6-4, 7-6 (9/7)

QF: bt Lloyd Harris (RSA) 7-6 (8/6), 6-3, 6-4

Daniil Medvedev (RUS x2)

RD128: bt Richard Gasquet (FRA) 6-4, 6-3, 6-1

RD64: bt Dominik Koepfer (GER) 6-4, 6-1, 6-2

RD32: bt Pablo Andujar (ESP) 6-0, 6-4, 6-3

RD16: bt Daniel Evans (GBR x24) 6-3, 6-4, 6-3

QF: bt Botic Van de Zandschulp (NED) 6-3, 6-0, 4-6, 7-5

Felix Auger-Aliassime (CAN x12)

RD128: bt Evgeny Donskoy (RUS) 7-6 (7/0), 3-6, 7-6 (7/1), 7-6 (10/8)

RD64: bt Bernabe Zapata Miralles (ESP) 7-6 (7/5), 6-3, 6-2

RD32: bt Roberto Bautista Agut (ESP x18) 6-3, 6-4, 4-6, 3-6, 6-3

RD16: bt Frances Tiafoe (USA) 4-6, 6-2, 7-6 (8/6), 6-4

QF: bt Carlos Alcaraz (ESP) 6-3, 3-1, retired, leg injury

With AFP Inputs