Novak Djokovic began his Wimbledon title defence with a rusty four-set win against Kwon Soon-woo on Centre Court on opening Monday.
Djokovic is a six-time winner of the Wimbledon Championships and has won the last three editions of the grass-court major.
Despite dropping the second set, the Serb found his feet as the match went on and secured his 80th Wimbledon match win 6-3 3-6 6-3 6-4 in just under two-and-a-half hours.
The victory makes him the first man or woman to have won at least that many singles matches at each of the four major tournaments.
Djokovic will take on either Thanasi Kokkinakis or Kamil Majchrzak in the second round.
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"I've said this a few times before, but this court is truly special for me," Djokovic said post-match on Centre Court.
"It's always been the court I dreamed of playing and winning on. All of my childhood dreams came true here on this court at this tournament, so of course, it's an absolute honour and pleasure to come back."
This was Djokovic's first official match on grass since winning last year's final against Matteo Berrettini and afterwards, he paid tribute to world No 81 Kwon, who had been an awkward opponent.
"Credit to Kwon for playing some really high-quality tennis," Djokovic said.
"I didn't have any lead-up, preparation tournaments or matches prior so you're always going to feel a little bit less comfortable than you would like to, particularly playing against someone as talented as him who stays close to the line and hits very cleanly on both sides.
"It was really difficult to hit through him, so I had to figure out a way tactically to get in control of the point. It wasn't easy."
In the third and fourth sets, Djokovic progressively increased the percentage of first serves he got in and produced 10 aces over the course of the final two sets.
As the match went on, he hit the same number of winners (12) in the third set as he had done during the first two combined.
After being made aware his victory handed him another piece of tennis history - being the first male or female player to have 80 wins or more at every major - he reiterated his dedication to the sport.
Djokovic said: "This sport has given me everything, I owe a lot to this sport. I love it still with all my heart, have a lot of passion for it and am as dedicated as anybody out there.
"I'm not one of the youngsters anymore, things change a little bit, but the love and flame for this sport still burns in me," he continued.
"At this stage of my career, I try to always play my best tennis at the Grand Slams and really deliver the best time on the most significant courts our sport has.
"Now that we've got to 80… let's get to 100!"
Hurkacz shocked, Cilic out due to positive test
Elsewhere in the men's draw on day one, Alejandro Davidovich Fokina stunned seventh seed Hubert Hurkacz.
Hurkacz was a semi-finalist last year but lost 7-6 (7-4) 6-4 5-7 2-6 7-6 (10-8) after a marathon contest on No 3 Court.
Davidovich Fokina, the 2017 Wimbledon junior champion, came back after being a break down in the fifth set and behind in the match tie-break.
The victory was Davidovich Fokina's first win at Wimbledon on his second appearance. The three-hour and 28-minute duel was his third career top-10 victory and he will take on either Federico Coria or Jiri Vesely next.
Former Wimbledon finalist Marin Cilic is out of the tournament after testing positive for Covid.
Cilic, who lost to Roger Federer in the final in 2017, was due to face Mackenzie McDonald in the first round but will be replaced by Nuno Borges.
"Hey guys, I am sad to share that I tested positive for COVID," Cilic wrote on Twitter.
"I have been self-isolating and was hopeful I would be ready but unfortunately, I am still feeling unwell & unable to compete at my best. I am heartbroken to be missing Wimbledon & to see my grass season end this way. [I am] Looking forward to competing next year!"
Casper Ruud earned his first main draw victory at the All England Club by defeating Albert Ramos-Vinolas 7-6 (7-1) 7-6 (11-9) 6-2.
Ruud hit 14 aces and 46 winners overall during the contest and capitalised on Ramos-Vinolas' greater double fault count (seven to three).
Nikoloz Basilashvili and Lukas Rosol delivered the first five-set match of the Championships, with the 22nd seed from Georgia prevailing 6-7 (4-7) 7-6 (8-6) 3-6 6-3 6-3.
Basilashvili will meet France's Quentin Halys in the second round, after Halys overcame his compatriot Benoit Paire in four sets 4-6 6-1 6-2 6-4.
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Francis Tiafoe started his fifth Wimbledon appearance with a straight-sets result against Andrea Vavassori 6-4 6-4 6-4 and spend just under two hours on court. The 23rd seed will now take on qualifier Maximilian Marterer, who overcame Aljaz Bedene 4-6 7-5 6-4 7-5.
Tommy Paul could also take on a qualifier in the second round after his 6-1 6-2 7-6 (7-4) win over Fernando Verdasco. Qualifier Max Purcell must beat Adrian Mannarino to make that happen.
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