Holger Rune was unsuccessful as he tried to challenge his own serve during his three-set defeat at the hands of Jannik Sinner.
Rune was eliminated from this year's ATP Finals after losing the decisive rubber against Sinner. Following Novak Djokovic's very own three-set win over Hubert Hurkacz (an alternate summoned to replace the injured Stefanos Tsitsipas), the Dane knew what was at stake.
A win of any kind was needed to secure his spot in the last four and thereby knock out defending champion Djokovic in the group stage. But that didn't happen, as the 20-year-old lost for the first time in three meetings against the red-hot Sinner.
There was a contentious moment early in the third set when Rune became the latest player to receive the full wrath of the Italian public inside the Pala Alpitour. It was expected that Sinner was going to enjoy nearly 100% of crowd support, as has been the case this tournament.
And Rune didn't do himself any favors trying to challenge his serve in spite of having played the point after Sinner's return. It was at a critical moment, at 40-40. The Dane stopped play as he "felt" his serve was long and was trying to buy a second serve.
Rune knew he had committed an unforced error having netted his second shot after the serve, which would give Sinner a break point. Chair umpire Aurelie Tourte requested for a replay of the footage after Rune challenged her call.
"Ladies and gentlemen, on the video you can see that after Mr Rune missed the shot he raised his finger, so the challenge is denied."
However, the Dane was unsuccessful, as he challenged after playing the shot. He was jeered by the Italian crowd as he tried to protest at the umpire. TV replays showed that Rune's serve was indeed long, but that didn't matter as he would save the break point and went on to hold serve.