Serena Williams’ coach Patrick Mouratoglu has posted a video online, showing himself training the tennis icon ahead of her second-round match at the French Open.

The Frenchman has trained Williams since 2012, helping her to win 10 majors and a gold medal at the London Olympics.

In total, he has won 31 coaching singles titles and four doubles titles, having worked with the likes of Anastasia Pavlyuchenkova, Laura Robson and Grigor Dimitrov.

The 50-year-old currently coaches men’s world number five Stefanos Tsitsipas and teenage prodigy Coco Gauff, along with Williams herself.

Nicknamed “The Coach”, Mouratoglu has accumulated a huge social media presence, with 365,000 Instagram followers and regularly shares videos and images featuring the players he trains.

Taking to his famous Instagram, the Frenchman posted a clip where he can be seen teaching the 23-time Grand Slam winner how to “cut the trajectory.”

Essentially, this involves running towards the ball instead of simply moving sideways, unless the ball is “really deep.”

In the video, the Coach throws balls to Williams as she practises forehands and offers words of encouragement to the 39-year-old. “Amazing”, he can be heard shouting. “Unbelievable.”

So far this season, the US star has struggled on clay, winning just two matches after an extended absence following the Australian Open.

She did, however, beat Irina-Camelia Begu in straight sets to set up a round two clash with another Romanian în Mihaela Buzărnescu.

If the three-time Roland-Garros winner can cut the trajectories as well as she seemed to do in training, she could be very hard to stop.