Carlos Alcaraz continued the defence of his crown on Wednesday with a win in four sets over Fabian Maroszan from Hungary.
Alcaraz, who beat Alexander Zverev in last year's final, ran away with the first set 6-1.
But his 25-year-old opponent offered stiffer resistance in the second.
After snaffling the Spaniard's service early in the set, he fought off three break points to hold on to his advantage, taking the second set 6-4 to level proceedings after 75 minutes on centre court.
Alcaraz surged through the third 6-1 in 25 minutes and from 2-2 in the fourth, the 22-year-old showcased his speed, touch and flair to reel off four straight games to give him the set and the match 6-1, 4-6, 6-1, 6-2 after two hours and nine minutes.
"It was a great match," Alcaraz told on-court interviwer Mats Wilander.
"I started really well but in the second set he played better. He was more aggressive.
"But I stayed strong and in third set, I played better and it was the same in the fourth set."
Injury
Elsewhere in the second round of the men's draw, seventh seed Casper Ruud aggravated a left knee injury during his four-set defeat to Nuno Borges.
"Certain movements out there are kind of what makes it painful," said the 26-year-old Norwegian.
"Certain shots are painful to do. When you're playing matches, you can't really control things in the same way as you can in practice. You do everything you can to get to every ball. Sometimes you kind of forget that this is a shot I shouldn't go for maybe in terms of pain in the knee."
Borges, the world number 41, came from behind to win 2-6, 6-4, 6-1, 6-0 and advance to the third round at the French Open for the first time.
Mariano Navone also reached the third round at the tournament for the first time following an impressive win over the big-serving American Reilly Opelka.
The 24-year-old Argentine prevailed 6-1, 7-6, 6-3 to set up a meeting with the eighth seed Lorenzo Musetti who surged past Daniel Galan 6-4, 6-0, 6-4.
"It was a solid performance from the beginning till the end," said Musetti. "I had some ups and downs during the first and the third set but I cannot complain about the level that I'm showing.
"They weren't easy conditions to play in but I managed to find out a way to show my tennis and my game. I think we both played a great, great match."
