The 39-year-old was given a tough first-round examination by big-hitting world number 102 Wu, who missed much of the last two seasons due to injuries, eventually winning 6-4, 5-7, 6-4, 6-4 after three hours and 12 minutes on Centre Court.

"Obviously better when you win in the end, it's not the first time that I'm talking about the significance of Wimbledon in my career and my life," said Djokovic.

"It was very challenging for me today. I'm feeling happy but not the freshest I guess. It didn't feel like the first round to be honest."

The Serb is now just two match wins short of equalling Roger Federer's all-time Wimbledon record.

"Playing on this surface, these kind of matches are decided on a few points, a few shots," said Djokovic, who was being cheered on by his family, David Beckham and rapper Bad Bunny.

"Thankfully I have 20-plus years of experience. It would be nice to combine experience with a new, fresh body."

He next faces former world number three Stefanos Tsitsipas in an intriguing second-round tie.

The Greek is now ranked 87th and split from his father and coach Apostolos ahead of Wimbledon in a bid to regain his best form.

But Djokovic has won each of the pair's last 10 meetings, including when he came back from two sets down to win the 2021 French Open final.

The seven-time Wimbledon champion is level with Margaret Court on the all-time Grand Slam winners' list.

He lost to eventual champion Jannik Sinner in last year's semi-finals as he failed to reach the final for the first time since 2017.

Djokovic, seeded seventh, could meet the world number one in the last four again next week.

Djokovic was pushed hard for the vast majority of the evening by Wu, but managed to do enough in the crucial moments to get over the line, saving 10 of 11 break points.

He saved two break points in the 10th game to successfully serve out the first set, but was broken for the only time in the match to drop the second before the roof was closed.

Djokovic came through a dramatic final game of the third set on his fourth set point, also staving off a break point as Wu desperately tried to avoid slipping one set from defeat, but in vain.

The Serb held in the sixth game of the fourth set from 0-40 down and then started to grimace and stretch his back.

He made his move shortly afterwards, though, breaking for a 5-4 lead before closing it out with a hold to love.