Novak Djokovic said he wouldn't have been surprised if his second-round match against Jacob Fearnley at Wimbledon went to a fifth set, but he's "very glad it didn't."

The seven-time champion at the All England Club beat his 22-year-old Scottish opponent 6-3, 6-4, 5-7, 7-5 on Centre Court on Thursday in another test of his fitness following recent knee surgery.

"Can I be playing better and moving better? Yes, absolutely," Djokovic said in an on-court interview. "So I'm hoping that as the tournament progresses each day or each match I'll be feeling a bit better."

Fearnley, a wild-card entry who recently finished playing college tennis at TCU, had a strong cheering section that erupted when he took the third set.

"He served very well. It was very difficult to break his serve. He made me work, definitely," Djokovic said.

The 24-time Grand Slam champion said he should have closed it out in straight sets but that he "was not really comfortable in my own skin, particularly in the third and fourth."

"Sometimes you have rough days where maybe you are not feeling your best," he added, "and of course it also depends on the opponent across the net. He made me earn this victory."

No. 7 seed Hubert Hurkacz became the third top-eight men's player to make an early exit as he retired from his second-round clash against Arthur Fils with a knee injury.

Having made a slow start, Hurkacz was on course to level the match at two sets apiece when he dived for a volley at the net in the fourth set tiebreak to go 8-7 up. Hurkacz landed badly and stayed on the turf to receive treatment on his right knee.

Hurkacz limped on after a lengthy medical timeout before producing another desperate dive shortly after, but his movement was severely hampered. He threw in the towel at 7-6 (2), 6-4, 2-6, 6-6 having gone down 9-8 in the tiebreak.

"It's very tough to win a match like this against a friend," Fils said in his on-court interview. "We were playing super good in the fourth set. We had some great points, and he was jumping everywhere. I'm really sorry for him, and I hope he will recover very quickly.

"Me, I'm focused on the next round."

Hurkacz showed flashes of his best form after a lackluster effort in the first two sets before joining sixth seed Andrey Rublev and eighth seed Casper Ruud in making an early exit.

Fils became the youngest Frenchman to reach the Wimbledon third round since 2005, when both Richard Gasquet and Gael Monfils did so as teenagers. He next faces Russian Roman Safiullin in his 10th tour-level match on grass.

"It's only my second year on grass. OK, I'm playing better than last year, but I still have so much to improve," Fils said.

Fils' 37-year-old compatriot Monfils joined him in advancing after beating three-time Grand Slam champion Stan Wawrinka 7-6 (5), 6-4, 7-6 (3) in a match that began Wednesday.

"It was a veteran battle. That's why we still love the game. We are just good friends," Monfils said. "Stan is someone I look up to. It's always a privilege to play him. Today I won, but I know the next one it could be him.

No. 9 Alex de Minaur secured a comprehensive 6-2, 6-2, 7-5 win over Jaume Munar, No. 10 Grigor Dimitrov came back from two sets down to defeat China's Shang Juncheng 5-7, 6-7 (4), 6-4, 6-2, 6-4, and American 14th seed Ben Shelton and No. 15 Holger Rune both rallied from a set down to advance.

American and No. 13 Taylor Fritz moved past Arthur Rinderknech 6-3, 6-4, 3-6, 6-4 to set up a third-round clash with Alejandro Tabilo, who battled past Flavio Cobolli in five sets.

The Associated Press and Reuters contributed to this report.