NEW YORK — Novak Djokovic took a first unsteady step toward completing the calendar-year Grand Slam on Tuesday as the Serb labored into the second round of the US Open with a (6-1, 6-7(5), 6-2, 6-1) win over dashing Danish teenager Holger Rune.
On paper, the contest was a total mismatch — an 18-year-old qualifier making his Grand Slam debut against a player chasing a 21st major title.
While the outcome was exactly what was expected, the effort needed by Mr. Djokovic to see off the fearless Dane, who battled to the end despite suffering cramp, was not.
“I started great. Played a really, really good first set,” said Mr. Djokovic. “After that, I don’t know, I was 4-3 serving in the second set, everything was working well, but then I just lost the first serve.
“I had until tonight tons of experience playing on this court, for him it was the first one.
“Still, you get nerves. You still are feeling a little bit rusty at the beginning.”
The match got underway amid a somewhat flat atmosphere inside Arthur Ashe Stadium, but the crowd were chanting the little-known Dane’s name after he stunned Mr. Djokovic to win the second set.
Aside from that, it was a controlled effort from the 34-year-old Mr. Djokovic, far different from the Serb’s last match on Arthur Ashe Stadium court which ended with him being disqualified after swatting a ball in frustration that struck a line judge.
The stone-faced world number one was all business from the start, breaking his opponent at the first opportunity and rolling through the set in just 26 minutes.
Playing his first event since a disappointing Tokyo Olympics, there were signs of rust and a lack of intensity, particularly in a sloppy second set when Mr. Rune broke him twice and forced the set to tie-break that he easily won.
But there was never any panic from Mr. Djokovic, who turned up the pressure in the third with an early break to regain control as Mr. Rune began to suffer cramp.
As Mr. Rune grimaced with every step, Mr. Djokovic showed his ruthless side, moving the youngster from line-to-line and taking the set 6-2.
Mr. Rune was determined to battle his way to the end, but a Djokovic victory was now certain and the Serb wrapped up the match by taking the fourth set 6-1.
“It was a crazy experience, playing against Novak on Arthur Ashe is probably one of the dream come true,” said Mr. Rune.
“To be able to win one set as well was great.”
The Dane said his fitness struggles made winning “impossible.”
“I had high belief in myself throughout the whole match,” he added.
“Unfortunately, my fitness let me down. — Reuters