Jimmy White was left shocked after Ronnie O'Sullivan expressed his anger during his World Snooker Championship quarter-final.
The seven-time world champion took his frustration out on the table at the Crucible after missing an easy pot in his match against Stuart Bingham.
O'Sullivan eased through the first two rounds in Sheffield as he aims to win a record-breaking eighth title in the coming days.
But Bingham was sure to give him a tougher test than Jackson Page and Ryan Day following his second-round win over Jack Lisowski.
Ronnie O'Sullivan shocked Jimmy White as he missed an easy red at the World Snooker Championship
Eurosport
Bingham raced into a 3-1 lead at the first mid-session interval on Tuesday, building on the momentum he gained from his previous night's win.
But O'Sullivan came back to level the match up at 3-3 and had a great chance to take a firm griphold of the seventh frame.
However, he uncharacteristically missed a red to spark a furious reaction, where he slammed his cue on the edge of the table.
Welsh snooker player Dominic Dale was on commentary at the time and said: "Ronnie showing some frustration there, I don't blame him.
"That was a poor one from him. Banging his cue, you don't like to see that."
O'Sullivan did return to win the frame and move into a 4-3 lead, before Bingham levelled it up at 4-4 after the first session.
But O'Sullivan's angry moment was a topic of discussion in the Eurosport studio afterwards and White revealed his surprise at the incident.
The six-time finalist said: "You don't often see him miss a red like this. You can't believe it.
"That was the first opportunity, the seventh frame, where he had a chance to get in front. It was a chance for him to get going.
"He did go 4-3 up [by winning this frame], but Ronnie has struggled in this match.
"He's had a few easy misses, he won't keep doing it, he will catch. Bingham needs to keep the belief and keep playing as he is."
When leading 2-0, Bingham decided to pursue a 147 break before taking a more conservative approach.
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Ronnie O'Sullivan slammed his cue on the table in an angry moment at the World Snooker Championship
Eurosport
White says the 47-year-old may regret not taking advantage of O'Sullivan being out of sorts.
He said: "He could have quite easily played to pot that red, make sure he got good on the yellow or the green.
"But he decided to go for the black, caught the jaw and [although] he potted the yellow, he missed the next red with a rest.
"He could have been 3-0 in front and really in control of the game.
Ronnie O'Sullivan was not happy as he missed a red in the seventh frame of the quarter-final
Eurosport
"Because at that stage, Ronnie was really struggling and he was getting a little bit angry."
O'Sullivan and Bingham will play the next eight frames of their match from 2.30pm on Wednesday afternoon.
The game will reach a conclusion later in the evening, with action starting at 7pm.