Dominik Koepfer received a point penalty during his third-round clash with Roger Federer at the French Open on Saturday when he spat on the court in anger.
The German player was left seething after a tight line call went against him on break point in the fourth set to hand Federer a huge advantage.
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Serving at 30-40, Koepfer thought he'd hit a clean winner to make it deuce, however the linesperson called his ball out and the chair umpire ratified the call after checking the mark.
That left Koepfer seething, who walked around the net to Federer's side and promptly spat on the line where he thought the ball had landed.
The World No.59 earned a code violation and point penalty for his troubles, as well as condemnation from commentators and fans.
"Koepfer, he lost his serve and then got a point penalty, well deserved," said Barbara Schett on Eurosport.
"It was disgusting behaviour there from the German. I have to say it."
Tennis great Chris Evert said: "It shows how much he wanted it, but I'm not defending him.
"That's certainly not a good thing to do! Nobody likes to see that, especially spectators. I don't think I've ever spat in my life."
While commentator Simon Reed said: "Oh, he shouldn't be doing this. Yeah, not good, he got a point penalty for spitting on the mark."
Fans were also left fuming over the 'disgusting' act.
Roger Federer announces shock withdrawal
If Koepfer wasn't already fuming after losing to Federer in four sets, he certainly will be now after the Swiss legend withdrew from the French Open on Sunday.
The 39-year-old, who has hardly played in the last 17 months because of a knee injury, suffered physically in his late-night victory over Koepfer that finished near 1am.
He subsequently decided to end his Roland Garros campaign before a fourth-round match against Italian Matteo Berrettini, citing his desire to stay fresh for a run at the Wimbledon title.
"After discussions with my team, I decided that I should withdraw from the French Open today," Federer said in a statement on Twitter.
"After two knee operations and more than a year of rehabilitation, it's important that I listen to my body and not rush back into competition."
Federer had said after Saturday's match that he was pondering whether to participate in the second week of the clay-court major as his season goal was Wimbledon - starting on June 28.
"We go through these matches ... we analyse them highly and look on what's next and we'll do the same tonight and tomorrow," he said.
"Because I need to decide if I keep on playing or not, or is it not too much risk at this moment to keep pushing or is this just a perfect way to just take a rest."
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