Stefanos Tsitsipas came very close to a disqualification during his quarter-final match at the 2023 Australian Open.
In 2020, Novak Djokovic was disqualified from his fourth-round match at the US Open against Pablo Carreno Busta after he hit one of the line judges.
Last year, when Nick Kyrgios played against Stefanos Tsitsipas at the Wimbledon Championships, the Greek hit the ball in anger and appeared to hit one of the spectators, as the Australian demanded a disqualification for him.
Tsitsipas wasn't disqualified from that match, but it seems that he didn't learn his lesson. During the 2023 Australian Open, he wasn't very far from being disqualified again.
The Greek player was in complete control of the match. He led 6-3, 7-6, and 4-3, and even had a 30-15 lead on his opponent's serve. He probably felt that he was close to winning that game and, ultimately, the match, which is why he was angry after he lost that rally.
After the winner from his opponent Jiri Lehecka, the ATP World No. 4 hit a ball in frustration. That wouldn't be an issue if one of the ball kids wasn't already trying to collect it.
Tsitsipas almost hit the ball kid, which would have very likely meant a disqualification for him. Former World No. 1, Jim Courier, who noticed the incident while providing commentary for Channel 9, called out the Greek player's dangerous act.
"I'm not sure if we're gonna get a replay of it Tsitsipas just got really lucky. He swings in anger and it nearly hits the ball kid. And if he does, you are shaking hands, losing this match. You cannot do that, that was dangerous."
"Djokovic got defaulted at the US Open a few years back for swatting a ball and hitting a linesperson. But there are still people on the court and if you hit them you are disqualified. If you hit someone in the stands in anger as well, you are out as well."