Novak Djokovic lost yet another gruelling match to end his Cincinnati Open campaign at the first hurdle against Thiago Agustin Tirante.

Djokovic comfortably took the first set, but eventually the heat and humidity of Cincinnati took its toll on the 39-year-old and he fell to the Argentine.

The Serbian needed a medical time-out after holding his serve in an epic 18-minute game, and it lead Brad Gilbert to call for several rule changes.

Taking to X, the former coach of Andy Murray, Coco Gauff, and Andre Agassi said: “I wish I could change the injury time out rules and comfort breaks.

More tennis news

“First thing I [would] get rid of: No evaluation time especially on a preexisting injury. Go back to three minute medical time out, that’s it. And [it] has to be on your serve or you forfeit the points. Bathroom breaks should be three minutes.”

There has already been controversy around breaks at the Cincinnati Open, as Rafael Jodar upset Denis Shapovalov by taking a break to sort out his shoelaces.

This has been a recurring theme in tennis so far this year, as Felix Auger-Aliassime complained about Alejandro Davidovich Fokina’s medical time out during their match at Wimbledon.

The Spaniard called for a medical time out mid-match while Auger-Aliassime was serving, which infuriated the Canadian.

Speaking in his post-match press conference, Auger-Aliassime said: “Now what I can say, though, is that I think the rule has to change. I think that obviously as long as the rule is like that, a player will use it to their advantage.

“I think that it’s very simple: if you’re hurt bad, or whatever you’re hurt, while the game’s going on of your opponent, in the middle of the game, the opponent is serving, the shot clock is on, basically when you’re hurt bad, you’re forfeiting every point until you can call the physio.

“If the physio helps you recover, you play your service game. If you’re hurt bad, then you retire, obviously. But to stop in the middle of an opponent’s service game and to be able to call the physio, I think that’s a disgrace of a rule. I don’t see any other sport where you can do that. I mark my words. It’s a disgrace of a rule.”

It certainly seems to be a controversy rumbling on and Gilbert wading in on the debate will only continue to put pressure on the organisers of the ATP and WTA Tours.

The Cincinnati Open continues until the 23rd August, when the finals take place in both the men’s and women’s draws.