Djokovic faces Griekspoor in the second round of the US open

World number one 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 hardcourts.