Ronnie O'Sullivan told eagle-eyed viewers exactly how he felt about his World Snooker Championship semi-final performance on Friday evening. The Rocket was tormented by Zhao Xintong in the afternoon session, and barring a brief glimmer of hope once play resumed later on, the onslaught continued into the evening.

O'Sullivan could hardly believe it when, at 7-15 down, he spurned a chance to start building a break by missing an easy red. The cue ball was not far from the cushion, but it was almost a straight shot into the bottom-left corner to continue clawing back ground on his vastly less experienced opponent.

There were groans and gasps from the crowd as a horrible miscue saw the red miss its mark by some margin. O'Sullivan's head dropped before it even reached the jaws, and the seven-time world champion returned to his seat with a grimace on his face.

BBC cameras then picked him up clearly mouthing the word 'embarrassing' twice. Commentator John Virgo said: "He must be so frustrated inside that he's come to this World Championship and not brought his A-game. In all honesty, he's done really well to get to the semi-final."

O'Sullivan, who ended up losing the match 7-17, had been far from complimentary about his own game since the tournament started. He took three months away from competitive action before arriving at the Crucible, and signs of rust were visible from the off.

After defeating Si Jiahui in the quarter-finals, which followed wide victories over Ali Carter and Pang Junxu, O'Sullivan told the BBC: "I’m just grinding it out. I’m playing awful and the cue feels awful. It’s the worst situation to be in as a snooker player.

"I’m still in so I’ll keep punching away, keep trying. [Si] had lots of chances. I was trying all sorts, trying to hold the cue in a different place to get a bit of feel, I’ll just try anything. He played poorly in the whole match really, let me off the hook loads of times, so I got lucky again."

The word 'awful' popped up again following the Rocket's defeat to Zhao, as he told the BBC: "I've been awful for quite a while. Those performances are in there, they've been coming out quite regularly recently. I'd just like to play alright and I just felt like I never gave him a game so that's a bit disappointing."