Mark Allen faces a fine from World Snooker after conceding a match-winning frame with 11 reds still left on the table at the World Grand Prix.
The former Masters champion was 3-1 down to Ali Carter and trailing 20 points to two in the fifth frame when he missed a straightforward yellow and screwed the white ball back into the middle pocket.
The Northern Irishman immediately conceded the frame, and with it the match, to gift Carter a place in the quarter-finals of the Coral Grand Prix, where he will play fellow Englishman David Gilbert.
— World Snooker (@WorldSnooker) February 7, 2019
Allen, who is currently sixth in the world rankings, later took to Twitter to apologise for his performance.
The Northern Irishman tweeted: "Bad day at the office. Sorry to anyone who had to watch that. Best of luck to @TheCaptain147 for the rest of tournament. Home to the family now #priorities."
Carter told ITV4: "We both started missing a lot and I think Mark missed the yellow there and he just saw red. We've all done it and fortunately for me it gives me the match, but I didn't want to win like that.
"We all make mistakes. I read in the paper the other day that Sergio Garcia hacked up a couple of greens and went into one in a bunker and you think to yourself 'What's he got to worry about?'
"But you get so entrenched in what you're doing and you are so frustrated, because it is your life. This sport is my life and golf is Sergio's life and it doesn't make an excuse but it gives a reason."
World Professional Billiards and Snooker Association rules state that "each member shall perform and compete to the best of his ability in each tournament in which he competes" and players are subject to disciplinary action if they concede a frame it is mathematically possible to win.