Novak Djokovic serves to Holger Rune during the US Open on Tuesday in New York City. Photo: VCG

 

World No.1 Novak Djokovic won without playing his best to reach the second round of the US Open on Tuesday in his quest for a calendar-year Grand Slam and record 21st major title.

The 34-year-old Serbian star dominated much of the way in beating 18-year-old Danish qualifier Holger Rune 6-1, 6-7 (5/7), 6-2, 6-1 after two hours and 15 minutes in the night feature at Arthur Ashe Stadium.

"It wasn't the best of my performances," Djokovic said. "At the same time, he played well in the second set when it mattered and I didn't serve well in the second set."

History-chasing Djokovic, who has won eight of the past 12 Grand Slam events, will next face 121st-ranked Dutchman Tallon Griekspoor, a rival the top seed admitted he didn't know much about.

"I know this court well," Djokovic said. "Hopefully that's going to help."

Djokovic would complete the first men's singles calendar-year Slam since Rod Laver in 1969 by winning the crown on the New York hard courts.

He would also break the deadlock for all-time men's Slam titles at 20 which he shares with Roger Federer and Rafael Nadal, both absent due to injuries, as is defending champion Dominic Thiem.

Earlier Tuesday, Tokyo Olympic champion Alexander Zverev stretched his win streak to 12 matches and warned he has his eyes on denying Djokovic the Slam.

Fourth seed Zverev, who beat Djokovic in an Olympic semifinal, dispatched American Sam Querrey 6-4, 7-5, 6-2.

"I hope in two weeks' time I'll be on an 18-match winning streak," said Zverev, who would claim his first Grand Slam title if he creates such a run.

The 24-year-old German, last year's US Open runner-up, hit 18 aces and 40 winners while never facing a break point in advancing after an hour and 40 minutes.

"Novak is chasing history," Zverev said. "But the young guys are going to try and get in the way of that. I'm going to try to give him a challenge as well."

Zverev, who next faces Spain's Albert Ramos-Vinolas, could face Djokovic in the semifinals.

French-born US qualifier Maxime Cressy fired 44 aces and saved four match points to upset Spanish ninth seed Pablo Carreno Busta 5-7, 4-6, 6-1, 6-4, 7-6 (9/7).

After beating Djokovic for a Tokyo Olympic bronze medal, the Spaniard's US Open ended slamming down his racquet in frustration.

"I'm really happy things are starting to pay off," Cressy said.

Japan's Kei Nishikori, the 2014 US Open runner-up, eliminated Italy's 113th-ranked Salvatore Caruso 6-1, 6-1, 5-7, 6-3. He next plays American Mackenzie McDonald with Djokovic a possible third-round opponent.

Italian sixth seed and Wimbledon runner-up Matteo Berrettini, a 2019 US Open semifinalist, defeated France's Jeremy Chardy 7-6 (7/5), 7-6 (9/7), 6-3.

Women's No.1 Ashleigh Barty, coming off wins at Wimbledon and Cincinnati, began her chase for back-to-back Slam titles by defeating Russian Vera Zvonareva 6-1, 7-6 (9/7).

The 25-year-old Australian next faces Denmark's Clara Tauson as she goes for her sixth title of the year.

Canadian sixth seed Bianca Andreescu, the 2019 US Open winner who skipped last year's event, struggled but outlasted Swiss Viktorija Golubic 7-5, 4-6, 7-5.