World number four Casper Ruud (24) reached the French Open last 16 on Saturday with a four-set win over China's Zhang Zhizhen (26).
Ruud, the runner-up to Rafael Nadal in 2022, dropped the first set before easing through 4-6, 6-4, 6-1, 6-4 against the world number 71.
Zhang was bidding to become the first Chinese man since 1936 to reach the fourth round in Paris.
"It was very tough in the first set, he was hitting many winners and I couldn't find a hole in his game," said Ruud.
"At 5-4 in the second set, he played some sloppy shots and that gave me the set, maybe the match," said Ruud, who hit 36 winners and saved seven of 10 break points.
Ruud, who was playing in the third round for a fifth successive year, will face either Nicolas Jarry of Chile or Marcos Giron for a place in the quarter-finals.
