Novak Djokovic admitted he was ring rusty on his Wimbledon return, but he still set another record by battling past South Korean Kwon Soon-woo in four sets.
The six-time champion, who was playing his first official match on grass since winning last year's final, found himself a break down in both the first two sets, dropping the second.
Kwon proved an awkward opponent with his aggressive shot-making but Djokovic, as he has so many times in the past, eventually found a way through the world number 81.
The 35-year-old has now become the only player in history to win 80 matches at all four Grand Slam events.
After sealing a 6-3, 3-6, 6-3, 6-4 victory with an ace, Djokovic said: “This court is truly special for me. It is the court I dreamt of playing and winning on, and all my dreams came true on this court.
“Credit to Kwon for playing some really high-quality tennis. Starting the tournament I didn't have any lead-up tournaments or matches so you are always going to feel less comfortable than you would like to, especially against someone as talented as Kwon.
“It was really difficult to go through him so I had to figure out a way tactically to get in control of the points.
“I faced a break point in the third which, if he had won, the match could have gone a different way.
“I owe a lot to this sport. I'm not one of the youngsters any more but the love and the flame for this sport still burns for me.
“At this stage of my career I try to save my best for the Grand Slams. Now we got to 80 wins, let's get to 100.”
Djokovic will now face Australian Thanasi Kokkinakis, who beat Pole Kamil Majchrzak 7-6, 6-2, 7-5, in the second round.
Third seed Casper Ruud eased through to the second round with a straight-sets win over Albert Ramos-Vinolas of Spain.
Ruud, who was runner-up to Rafael Nadal at the French Open earlier this month, came through 7-6, 7-6, 6-2.
The Norwegian had fallen at the first-round stage in his previous two visits to the All England Club.
He will face France's Ugo Humbert, who beat Tomas Martin Etcheverry of Argentina 6-3, 3-6, 4-6, 6-3, 6-4, for a place in the last 32.
British No 1 Cameron Norrie became the first UK player to win at this year's championships when he beat Spain's Pablo Andujar 6-0, 7-6, 6-4. He will face another Spaniard, Jaume Munar, in the next round.
Spaniard Alejandro Davidovich Fokina won a final-set tiebreak against Hubert Hurkacz of Poland to knock out the seventh seed and last year's semi-finalist.
The 23-year-old's 7-6, 6-4, 5-7, 2-6, 7-6 victory was his first at Wimbledon after his opening round defeat on debut last year.