World No. 1 Jannik Sinner advanced to the third round of Wimbledon after a straight-sets victory over Portugal’s Nuno Borges on Tuesday, but questions remain about the defending champion’s form ahead of an expected heatwave at the All England Club. Temperatures around 30ºC are forecast for the second week of the tournament, raising concerns about Sinner’s ability to maintain his performance level under harsher conditions.

Sinner’s opening match had been a difficult five-set struggle against Serbia’s Miomir Kecmanovic, marked by mobility issues and physical discomfort, including bleeding from a toenail. While Tuesday’s 7-6, 7-6, 6-4 win was more composed, the 24-year-old Italian still appeared far from his best. Analysts noted that his forehand strokes lacked the fluidity typically associated with his playing style, and his footwork on grass courts remains a concern.

Sinner himself acknowledged these challenges during his post-match press conference. When asked directly about his forehand, he admitted it was below his usual standard. He expressed some uncertainty about coping with the upcoming heat, noting that the warmer spells would come deeper into the tournament.

The issues have persisted since the French Open, where Sinner withdrew in the second round against Juan Manuel Cerundolo due to what was initially attributed to heat, though the player later cited illness. Since then, he has opted out of the usual grass-court warm-up event at Halle, instead undertaking medical testing in Milan and training in Monte Carlo to better prepare for Wimbledon conditions. However, the absence of competitive match play on grass appears to have left him lacking rhythm, which is crucial for transitioning effectively from clay courts.

Sinner described the start of his Wimbledon campaign as “tough” but expressed hope for improvement, citing the need to be more aggressive, improve movement on grass, and enhance his return of serve, particularly on second serves. He is set to face American Jenson Brooksby in the third round, whose unorthodox game could present a different kind of challenge.

Meanwhile, Novak Djokovic, a multiple Wimbledon champion and the tournament favorite at 39, displayed near-flawless form in a straight-sets win over Stefanos Tsitsipas on Tuesday. Djokovic committed just seven unforced errors in a 6-3, 6-4, 6-2 victory and appeared relaxed and confident, even sharing a lighthearted moment with a ball girl during the match. His form positions him as a strong contender for a record-tying 25th Grand Slam title.

The potential semifinal clash between Djokovic and Sinner now looms as a compelling matchup, contrasting Djokovic’s composed dominance with Sinner’s struggle to regain full sharpness under challenging conditions. As the heat intensifies at Wimbledon, how Sinner adapts could determine the trajectory of his title defense.