Jannik Sinner moved a step closer to defending his Wimbledon title with a composed victory over Jan-Lennard Struff to reach the semi-finals.

The world number one has yet to hit his best form at the Championships but acted decisively in key moments to secure a 7-5 7-6 (7-4) 6-3 win over Germany’s 74th-ranked Struff.

The Italian also showed no signs of being affected by the 30C temperatures, following his struggles with the heat in his shock second-round exit at this year’s French Open.

Asked about struggling in the scorching conditions at Roland Garros, Sinner dryly responded: “Thanks for reminding me!

“We worked a lot after Paris trying to understand what went wrong and prepared in the best possible way.

“It was a huge test today. I felt comfortable on the physical side, a good step forwards.”

Sinner could face Novak Djokovic next, in a repeat of last year’s semi-final, if the 24-time Grand Slam champion beats Felix Auger-Aliassime later on Tuesday.

After being taken to a decider against Miomir Kecmanovic in his opening match, Sinner has not dropped a set in his past four matches.

However, not all of those victories have been straightforward as the scoreline suggests, and the top seed has yet to find his best form at SW19.

That has yet to prove a major problem for the 24-year-old, who has upped his level when needed to claim the decisive breaks and get himself over the finish line.

But, with world number 48 Nuno Borges being the highest-ranked opponent he has faced so far, it remains to be seen how he will fare against someone like Djokovic or fourth seed Auger-Aliassime.

Against Struff, Sinner endured a slow start and was taken to deuce in three successive service games, while the 6ft 4in German cruised through his.

But Sinner clung on and remained composed to first break for a 6-5 lead before serving out the opener to take the lead.

After trading breaks in the second set, Struff had the chance to level the tie when he brought up a set point, but Sinner’s serve saw him out of trouble and he breezed through the tie-break.

The four-time major winner remained relaxed as he dropped just four points on his serve in the third set and, after striking the decisive blow at 4-3, confidently served out the victory to seal his spot in the final four.