London: Top seed Novak Djokovic overcame a dogged challenge from 81st-ranked Korean Kwon Soon-woo and his own grasscourt rustiness to reach the Wimbledon second round with a 6-4 3-6 6-3 6-4 victory on Monday.
The defending champion, bidding for his fourth Wimbledon title in a row and his seventh overall, looked out-of-sorts at times against Kwon, who brought a lively mixture of tennis, from booming forehands to delicate drop-shots, onto Centre Court.
Djokovic had not played a grasscourt warm-up tournament and he admitted that did not help his game against a tough opponent, 11 years his junior.
"I didn't have any lead-up or preparation tournaments prior to this so you're always going to feel a bit less comfortable than you would like, particularly if you're playing against someone as talented as Kwon who stays close to the line and hits really clean," he said.
"It wasn't easy. I had to put some variety in the game. The serve helped but at this level one or two shots decide a winner."
The 24-year-old Korean broke Djokovic's serve in the fourth game of the second set and went on to win it with a drop-shot and a big serve.
But the Serb, aiming to win a 21st Grand Slam title, recovered enough of his trademark consistency to see off the challenge.
He secured victory with an ace on his first match point and will next meet either Thanasi Kokkinakis of Australia or Poland's Kamil Majchrzak.
It was Djokovic's 80th Wimbledon win and he became the only man to have won 80 matches at all four Grand Slam tournaments.
The Serb, who won three Grand Slams last year, missed out the Australian Open in January after being deported because he was not vaccinated against COVID-19.
He lost in the French Open quarter-finals to eventual champion Rafa Nadal who is seeded second at Wimbledon.