PARIS (AP) — Stefanos Tsitsipas was in a reflective mood after beating Zhang Zhizhen, 6-3, 6-3, 6-1, to reach the fourth round of the French Open on Friday, May 31.

The 2021 runner-up says tennis plays a fundamental part in shaping his thinking.

“I get the feeling that without tennis my life would have been so much different, with regards to challenging myself and setting personal goals for myself,” Tsitsipas said. “Tennis helps me fill out those dreams and fulfil my deepest desires as a human being.”

The ninth-seeded Tsitsipas, who won the Monte Carlo Masters in April, feels his game is in good shape.

Next up for the big-serving Greek is unseeded Italian player Matteo Arnaldi.

“I have been keeping an eye on him the last six months,” Tsitsipas said. “He’s a very good fighter.”

Arnaldi advanced by eliminating sixth-seeded Andrey Rublev 7-6 (6), 6-2, 6-4.

Rublev came as a contender after winning the Madrid Open this month but he showed frustration against Arnaldi for his lack of precision, committing 37 unforced errors and four double faults. After netting a forehand in the third set, Rublev smashed his racket on his knee four times.

“I am completely disappointed with myself, with the way I behaved, the way I performed, and I can’t remember ever behaving worse in a Grand Slam tournament,” he said. “It was the first time I ever behaved that badly.”

Arnaldi disagreed.

“He does those things almost every match. Personally, I don’t pay too much attention,” Arnaldi said. “But it definitely does give me a little confidence, because it means I am giving him trouble, and what I was doing was working.”

No. 2 Jannik Sinner of Italy progressed by downing Pavel Kotov 6-4, 6-4, 6-4. The Australian Open champion next faces Frenchman Corentin Moutet.

Two-time major winner Carlos Alcaraz also advanced after beating 27th-seeded American Sebastian Korda 6-4, 7-6 (5), 6-3. Alcaraz was a semifinalist last year at Roland Garros, losing to Novak Djokovic.

On the women’s side, top-ranked Iga Swiatek reached the fourth round by beating Marie Bouzkova 6-4, 6-2. The three-time French Open champion from Poland won on her fourth match point, celebrating another Roland Garros victory on the day she turned 23.

Former French player Fabrice Santoro did the post-match interview and got the crowd on Court Philippe Chatrier to join in with him as he sang “Happy Birthday.” Swiatek put her head in her hands, shyly, then lifted it up and smiled broadly.

The match was not the thrill-a-minute contest she had with Naomi Osaka in the second round, when Swiatek saved a match point and grabbed the last five games.

Still, Bouzkova held on. She saved one match point with a forehand winner, and Swiatek hit a forehand wide on another. A crisp forehand down the line sealed Swiatek’s win at the fourth attempt.

Next for Swiatek was unseeded Anastasia Potapova.

No. 3-seeded Coco Gauff beat Australian Open semifinalist Dayana Yastremska 6-2, 6-4 but fellow American Sofia Kenin was stopped.

Kenin lost 6-2, 7-5 to unseeded Danish player Clara Touson, who has lined up two-time Wimbledon runner-up Ons Jabeur. The eighth-seeded Tunisian won against No. 31-seeded Canadian Leylah Fernandez 6-4, 7-6 (5).

Wimbledon champion Marketa Vondrousova defeated Frenchwoman Chloé Paquet 6-1, 6-3. The fifth-seeded Czech, a runner-up at Roland Garros in 2019, next faces qualifier Olga Danilovic, ranked 125th.

Danilovic beat Donna Vekic 0-6, 7-5, 7-6 (8) to make her first fourth-round appearance at a Grand Slam tournament. Danilovic lay on her back and cried as she took in her victory.

Italy’s Elisabetta Cocciaretto upset No. 17 Liudmila Samsonova 7-6 (4), 6-2 on Court Suzanne Lenglen to also reach the last 16 at a Grand Slam for the first time.

She has Gauff next.

For the fourth consecutive day, rain interrupted play. There was a delay of about 1 1/2 hours on Friday followed by another delay in the evening.