Marathon man Carlos Alcaraz was back at it at the Queen’s Club on Thursday. Less than two weeks after he won a thrilling five-set match to defend his French Open crown, the world No. 2 found himself dragged into another long battle in London.

Alcaraz needed three hours and 23 minutes to beat countryman Jaume Munar 6-4 6-7(7) 7-5 in the second round. But he wasn’t always his positive self during the match. He approached the umpire after becoming frustrated with the speed of the shot clock and, later in the evening, said: “They have to change that.”

Both Alcaraz and Munar became frustrated with the speed of the shot clock during the mega 101-minute second set, approaching the umpire to ask about it.

The No. 1 seed received a time violation on his serve after a lengthy point and wasn’t pleased. He later walked up to the chair and, when told the shot clock was running properly, sarcastically joked: “That’s crazy”.

During another chat with the umpire, he protested: “Why? Why you can’t stop? I finished the point at the net, I need to go to the towel, I need to do my routine. Yeah but I ask for the towel many times, they bring it to me, and still I don’t have time to go, you know?”

Commentator Nick Lester was surprised by Alcaraz’s frustrations. “That is quite an unusual scene for Alcaraz to be angry is the wrong word but a little irate. We don’t often see that with him. Cearly feeling somewhat aggrieved,” he said.

Alcaraz went on to lose the second set in a tiebreak. He double faulted while match point up, and Munar soon converted his eighth set point to force a decider. It was a rollercoaster final set – Alcaraz led 2-0, then lost four games in a row before storming back to win.

Afterwards, the five-time Grand Slam champion voiced his grievances with the shot clock and said he had been unable to properly prepare for each point.

Alcaraz explained: “It was a really long match. The conditions today was extreme with the heat. It was really, really hot out there, and yeah, really long rallies, long games. I felt like I had no time to recover between points. I was in a rush all the time.

“So it was kind of I can’t approach the next point in appropriate way. I mean, that talk with the umpire, it wasn’t because of that I didn’t lose the focus, but it was a problem all the time with all the clock.

“Jaume talked to the umpire with the same thing. They have to change that. But yeah, I mean, they have to know where to put the clock, you know, right after the point or wait a little bit, because after long points, long rallies, I finish the point at the net, I should have a little bit more of time just to approach the next point in a proper way. That’s what I felt today.”

The shot clock wasn’t the only thing Alcaraz struggled on Thursday. The top seed confessed that he found it difficult to stay positive, even though he’s known for his smiley demeanour on the court.

He added: “Yeah, it’s really important to think positive all the time. Today there were a few moments that I didn’t think positive at all.

“But I didn’t give up. So I think that’s the most important thing. So probably negative thoughts come to your mind in few moments, but the most important thing is you don’t give up. You just keep fighting. You just have to keep playing.

“Know that the opponent was going to give you chances to put yourself into the match again. That’s what I thought today. Just keep fighting and show the opponent that if he wants to beat you, he has to play at his best level. I think that’s a great mentality, a great thing to show to the opponent.”