Roger Federer lost his cool at the French Open on Thursday in a rare blow-up at the chair umpire and opponent Marin Cilic.
The 20-time grand slam champion was left fuming in the second set when he was handed a time violation for taking too long in between points.
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Federer had a fiery argument with chair umpire Emmanuel Joseph and even dragged Cilic into his rant.
"Marin, am I playing too slow?" Federer asked, to which Cilic responded he was.
After winning his first-round match on Monday, Federer spoke about the strange feeling of having to handle his own towel because of coronavirus rules.
He argued that point to the umpire and to Cilic on Thursday.
"I understand the rule," Federer protested to Cilic.
"I'm going from one corner to the next trying to get my towel. I'm not doing it on purpose."
Federer again vented to the umpire at the change of ends, clearly frustrated by the warning.
"I don't even dare to go my towel anymore," he said to Joseph.
The dispute lasted several minutes and seemed to unsettle Federer, however he regrouped to win 6-2 2-6 7-6 (4) 6-2.
"I guess I'm just new to the new tour," he joked after the match, referring to the time issue.
Tennis fans and pundits were rather stunned by Federer's rare outburst.
Roger Federer brushes off rules 'misunderstanding'
The flashpoint with the umpire came while he was receiving serve, with the laws of tennis insisting the receiver play to the speed of the server.
"I just feel like it was a misunderstanding on many levels," Federer added.
"I didn't feel like I was playing particularly slow, and with the towels, quite honestly, if I want to go to the towel, now I can't go to the towel anymore, it's okay, I get it.
"I understand playing to the server's pace, I have done it in hundreds of matches, and I always feel like I don't make my opponent wait very much, but clearly Marin wanted to go faster."
The Swiss legend is playing just his third tournament since losing in the Australian Open semi-finals to Novak Djokovic in 2020.
In between, he underwent two knee surgeries while the pandemic saw new rules introduced - including players, rather than ball boys, having to fetch their towels.
Federer, who turns 40 in August, said he was somewhat surprised by his strong performance.
"I didn't think I could play at this level for two hours against Marin," Federer said.
"I finished by serving really well. It shows I have something in reserve, I have some energy left and that's really good for my confidence."
Novak Djokovic cruises into third round
Earlier, World No.1 Djokovic strolled past Uruguay's Pablo Cuevas 6-3 6-2 6-4 to progress to the third round.
Cuevas showed flashes of resistance but the top-seeded Serbian lifted when needed and produced some sublime winners off his backhand to continue his chase for a 19th grand slam.
Djokovic's win set up a clash against Lithuania's Ricardas Berankis, who beat Australian James Duckworth 7-5 2-6 7-6 (4) 6-0.
"I think the third set was really difficult for me," Djokovic said, speaking in impressive French during his on-court interview.
"I raised my game. I stayed focused, I found my serve when it was important."
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