Novak Djokovic was sensationally defaulted from the US Open after hitting a linesperson with the ball during his fourth-round match against Pablo Carreno Busta.
World number one Djokovic was the clear favourite to win the grand slam at Flushing Meadows but remarkably exited the tournament on Sunday.
After dropping serve to fall 6-5 behind in the first set, Djokovic fired a ball behind him and hit the linesperson.
The woman audibly gasped for air as the Serbian immediately apologised, joining another judge in helping her.
The victory was awarded to Carreno Busta following a lengthy conversation between the match referees and Djokovic, who could be heard saying: "I understand, you have no choice."
Djokovic, who was 26-0 in 2020 going into the match, had grown increasingly frustrated through the early stages of the contest as Carreno Busta stood his ground with brave defence.
The Spaniard closed out the first break point Djokovic stylishly forged in an eight-minute eighth game, but the top seed's dominant serving continued to pile the pressure on his opponent.
Carreno Busta would not relent, though, staving off three set points from 0-40 down to prompt a suddenly irate Djokovic to lash at the ball for the first time.
He avoided punishment for that incident but soon went down holding his left shoulder after slipping.
Carreno Busta executed a fine drop shot for the first break of the match and, as he headed back to his seat, Djokovic committed his costly error.
"It's tough for you whatever call you make. I understand," Djokovic told the officials, although he continued to protest his case.
The decision was eventually made, and the two players shared a handshake to conclude a stunning turn of events.
Djokovic had already been the subject of some scrutiny coming into the New York major, having organised an Adria Tour event at which he and other leading players tested positive for coronavirus.
He battled a neck issue as he won the Western & Southern Open, while he has been involved in the formation of the breakaway Professional Tennis Players Association.