MUMBAI, Sept 16 (Reuters) - Inordinately long toilets breaks or medical timeouts at critical moments could soon be a thing of the past in men"s tennis with the ATP Tour planning to impose stricter rules, a source at the men"s governing body told Reuters. The practice has long been a bugbear of players, most recently at the U.S. Open where Stefanos Tsitsipas was accused of gamesmanship by Andy Murray for taking a lengthy trip to the bathroom at a critical point in their first-round match. The Greek world number three, who won the match, denied the charge and said he had broken no rules as there were no time limits on bathroom breaks. "There will be a change to the rules for bathroom breaks and on-court medical timeouts as well," an ATP source told Reuters. "I hope that before the next season begins in January, we will have a stricter rule when it comes to toilet breaks and medical timeouts." Murray was furious with Tsitsipas after the Greek"s break ran close to eight minutes, with the Briton saying the disruption had an impact on the outcome of the match. In his next match, Tsitsipas left for the locker room for more than seven minutes after losing the third set, and was jeered by the Arthur Ashe Stadium crowd on his return. "I think it"s getting to the point where it"s definitely becoming a big issue," the source added. "It"s been an issue for a long time but we are taking quite a serious approach now to try and change it." Former U.S. Open champion Sloane Stephens, who sits on the WTA players council, said players who took extended bathroom breaks were guilty of gamesmanship and called for governing bodies to change rules. read more An ATP spokesperson said during the tournament that a review of rules around toilet breaks, as well as medical time outs, had been an area of focus and remained a work in progress. The WTA said that it was "always open to conversation and evolving rules if changes are necessary". Alexander Zverev, who objected to Tsitsipas leaving the court during their Cincinnati semi-final last month, said the Greek"s behaviour at Flushing Meadows was "unacceptable". However, Tsitsipas found support from world number one Novak Djokovic. "I"ve got to stand for Stefanos Tsitsipas," Djokovic said at the U.S. Open. "I don"t think he"s doing anything wrong. I support him. "The rule is not clear. Of course you can argue it"s all relative, everyone sees it differently. "This was a hot topic last couple of weeks. I think he didn"t deserve that much attacks that he was getting in the media from everyone."