WATCH: Jannik Sinner seen working on his recent weakness ahead of China Open

Clips from Jannik Sinner's practice sessions before the 2025 China Open in Beijing may have given fans an insight into what he wants to improve most.

Sinner's opening-round match in the Chinese capital will be against Marin Cilic. The Italian has not played a match in any competition since losing the 2025 US Open final in four sets to Carlos Alcaraz.

Although Alcaraz's superb level in that match meant beating him would have been very challenging regardless, Sinner's first serve percentage of 48% made it near impossible to overcome his biggest rival.

Despite reaching the final, Sinner struggled with a low first serve percentage throughout the tournament. The rest of his formidable game was still enough against other opponents, but not against Alcaraz.

Sinner has been in Beijing for a few days already in preparation for the China Open. A couple of clips from his practice session were short, but they still gave an insight into what he is working on with his team.

The first video contained what appears to be an unconventional attempt to help Sinner fix his serve. When the ATP world No. 2 leaned back slightly during his service motion, a team member poked him in the back with a racket.

That trick was repeated a second time. Sinner or someone near him would have to explain what the exercise sought to achieve, but it could be as simple as getting him to lean back the correct amount before his leg drive.

In the second video, Sinner practiced his service motion without a ball or anyone on his team standing near him, probably feeling he needed to be comfortable with any alterations before hitting serves.

Improving the first serve percentage could be crucial for solving his issue against Alcaraz since the start of 2024. Despite their matches rightly being lauded for their high quality, Sinner has lost seven of his last eight encounters against him.

That includes being 0-4 on hard courts despite that being Sinner's strongest surface. The Italian's domination against other ATP players will mean little if Alcaraz routinely denies him at the final hurdle.

The four-time Grand Slam champion played without a permanent physiotherapist at the US Open after splitting with Ulises Badio a few days before Wimbledon, despite achieving great results with him on the team.

When he arrived in Beijing, Sinner was pictured with Alejandro Resnicoff, an experienced physiotherapist who has worked on the ATP Tour before. It is uncertain whether he is a permanent appointment to Sinner's team.

Someone with Resnicoff's experience seems like an ideal addition. However, the same was said when Sinner appointed Novak Djokovic's former team members Marco Panichi and Badio, but he elected to split from them.

Panichi's departure led to him reappointing Umberto Ferrara. That was hugely controversial since Ferrara played a pivotal role in his testing positive for clostebol at the 2024 Indian Wells Open, which led to a three-month suspension earlier this year.