The investigation was commissioned by the governing body in October 2021 following accusations of domestic abuse by Zverev’s former girlfriend Olya Sharypova.

It was carried out by third party investigator The Lake Forest Group (LFG), who concluded that due to a lack of reliable evidence and eyewitness reports and conflicting statements by Sharypova, Zverev and other interviewees, that it was unable to substantiate the allegations of abuse, or that any of the ATP’s On-Site Offences or Player Major Offences rules were breached.

The primary focus of the investigation was alleged abuse that took place during the 2019 ATP Masters 1000 tournament in Shanghai, although the investigation also covered alleged misconduct in other locations, including Monaco, New York and Geneva.

As part of its investigation LFG conducted extensive interviews with both Sharypova and Zverev, as well as family, friends, tennis players and other parties involved with the ATP Tour.

It also reviewed submissions by both Sharypova and Zverev, including text messages, audio files and photos, as well as material voluntarily taken from electronic devices belonging to Zverev.

"The seriousness and complexity of these allegations required an extremely thorough investigative process and considerable resources," said ATP chief executive Massimo Calvelli.

"It also required us to turn to specialist investigators, which was new ground for ATP.

"We ultimately believe the exhaustive process was necessary to reach an informed judgement.

"It has also shown the need for us to be more responsive on safeguarding matters.

"It is the reason we’ve taken steps in that direction, with a lot of important work still ahead."

The ATP says it reserves the right to re-evaluate the verdict if new evidence comes to light or legal proceedings reveal violations of its rules.

Zverev is currently ranked number 14 in the world, with his best result at a Grand Slam coming when he was the losing finalist at the 2020 US Open, after being beaten in five sets by Austria’s Dominic Thiem.

Zverev claimed the Olympic men’s singles gold medal at Tokyo 2020 after beating Karen Khachanov, who was representing the Russian Olympic Committee, in straight sets.