WATCH: Jannik Sinner retires in Shanghai after struggling to walk

Jannik Sinner's 2025 Shanghai Masters campaign ended much more swiftly than anticipated after he retired from his round of 32 match against Tallon Griekspoor.

Sinner was the defending champion, beating Novak Djokovic in the 2024 final. He started as an overwhelming favorite to retain the title after Carlos Alcaraz withdrew from the tournament with an injury.

Despite his outstanding results since the start of 2024, Sinner has consistently had problems against Alcaraz. The 22-year-old's absence increased everyone's chances of going far in Shanghai, but more success for the Italian in Shanghai felt inevitable to some.

However, Tallon Griekspoor did not read that script. The Dutchman never shows fear against any opponent, and he troubled Sinner from the start with aggression from the baseline and a willingness to move forward.

Sinner took the opening set on a tiebreak, but that did not rattle Griekspoor. He won the second 7-5, and it seemed like the contest could go to the wire. Instead, the match suddenly ended when Sinner's body broke down.

At 7-6, 5-7, 2-3, Sinner began cramping so severely, as can be seen in the videos below. A physio got him to his chair and attempted to help him feel better. Unfortunately, those efforts proved in vain.

After two hours and 35 minutes of outstanding tennis from both, Sinner retired. Griekspoor was gracious when shaking hands and seemed genuinely disappointed that the match did not reach a natural conclusion.

Although the rallies were intense, and cramping has happened to many players, Sinner's experience is quite concerning since his body breaking down has often been an issue for him.

Sinner's physical condition has undoubtedly improved, and he does not cramp as often as before. His five-hour and 29-minute French Open final against Carlos Alcaraz, despite losing, was a testament to the 24-year-old's improved endurance.

But Sinner has now retired in hot conditions twice during the past two months. The first was against Carlos Alcaraz, just five games into the 2025 Cincinnati Open final, and now against Griekspoor in Shanghai.

While Sinner and his team deserve considerable credit for his progress during the last few years, the consistent cramping and feeling dizzy in energy-sapping conditions is something they probably speak about and work on regularly.

After winning in the opening round, Alexander Zverev lamented the Shanghai courts being slower than in previous years, and claimed that they are being made similar worldwide because organizers want Sinner and Alcaraz to succeed.

Those remarks followed Roger Federer talking at the 2025 Laver Cup about how organizers probably slow courts down because they would prefer Alcaraz and Sinner to meet in the final, because that drives more interest and engagement to the event.

Ironically, Alcaraz is not competing in Shanghai because of his injury, and Sinner may not have cramped up if the courts were faster, which would have prevented so many lengthy rallies. Zverev and Federer's remarks generated a polarized reaction among fans.