Novak Djokovic’s Cincinnati Open run ended at the first obstacle, as the 39-year-old was beaten by Thiago Agustin Tirante after a draining contest that turned sharply in the Argentine’s favour.

Djokovic opened strongly and took the first set with ease, but the match grew tougher as the heat and humidity in Cincinnati began to tell. The Serbian later required a medical time-out after surviving an exhausting 18-minute service game, a moment that prompted Brad Gilbert to argue for changes to the rules around injury breaks and comfort breaks.

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

“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.”

The issue has already caused debate in Cincinnati, with Rafael Jodar drawing attention after taking a break to deal with his shoelaces in his win over Denis Shapovalov.

It has also been a familiar talking point elsewhere this season. At Wimbledon, Felix Auger-Aliassime criticised Alejandro Davidovich Fokina’s medical time-out during their match, saying the rule should be changed because players can use it to their advantage. Speaking after that match, he 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.”

With the discussion showing no sign of fading, Gilbert’s intervention adds further pressure on the ATP and WTA Tours as the Cincinnati Open moves toward its finals on 23rd August.

Alexander Zverev booked his place in the third round of the Cincinnati Open after a hard-fought win over Cameron Norrie, but the match also highlighted a persistent problem in the sport.

Zverev dropped the opening set against the Briton, then answered with a strong surge to take the next two sets by identical 6-3 scorelines and close out the contest. Yet the result came only after the pair finished the final match on the main court’s order of play, pushing the contest deep into the night.

The match ended after 2am, a finish that should not be part of professional tennis. Both players were then still expected to handle press obligations and begin recovery work, leaving little room for rest. By the time they could realistically get to bed, it would likely have been around 5am at the earliest.

That kind of schedule is particularly concerning for Zverev, who is trying to navigate back-to-back Masters events before the US Open. He entered the Cincinnati Open as top seed, just as he had at the Canadian Open, and this kind of late finish could complicate his preparation for the season’s final Grand Slam.

Zverev now moves on to face Terence Atmane for a place in the fourth round. How he responds physically will be watched closely, because the demands of playing so late are difficult to ignore.

The broader issue is one of player welfare. Late-night finishes disrupt recovery, create unnecessary strain, and are unsustainable for both players and supporters. A curfew at ATP Tour tournaments would go a long way toward addressing a problem that should not be left unresolved.

Thiago Agustin Tirante produced one of the surprises of the Cincinnati Open, defeating Novak Djokovic in the second round and ending the three-time champion’s run earlier than expected.

Djokovic opened with a straightforward 6-2 first set, but Tirante responded strongly to claim the next two sets and send the Serbian out at the second-round stage. The result was a major setback for Djokovic, who had arrived among the leading contenders with Carlos Alcaraz and Jannik Sinner not in the draw. His physical problems resurfaced, and he was unable to find a way past the Argentine.

Tirante will now move on to meet Martina Landaluce for a place in the fourth round of the Masters 1000 event.

After the match, Tirante reflected on the pressure of facing Djokovic for the first time. Speaking to The Tennis Channel, he said: “I was very nervous. I think the people saw it in the first set. I think I don’t do very well, you know. It was my first meeting with him. I don’t even practice with him never.

“So it was all new for me to play in the central court here against him. You say Novak and you think tennis, you know? So yeah, I was very nervous, but I think I do very good my job after with my team to give that off.

“I spoke with my team before the match, [they said] ‘Never give up’. I think that’s was the key, keep believing in me and and in my team because it was very very tough but I think that helped me because I don’t have more nerves after that game because I very tired.”

Djokovic did not close the door on another Cincinnati appearance before the end of his career. In his post-match press conference, he said: “I certainly hope so, but unfortunately, at this point it seems more likely that I won’t. However, we’ll see what the future holds.”

The match marked Djokovic’s first Cincinnati Open appearance since 2023, when he lifted the title. He has now won three titles at the Ohio event, but this was the first time since 2007 that he was beaten in the second round. That earlier defeat came against Carlos Moya, who retired in 2010, underlining Djokovic’s remarkable longevity on the ATP Tour.

His next scheduled event is the US Open, where he will continue his bid for a 25th Grand Slam title. He is expected to be the fifth seed at Flushing Meadows, depending on how the rest of the Cincinnati Open unfolds.