Ronnie O'Sullivan will be feeling "a little bit embarrassed" after losing every single frame in his Friday morning session with Zhao Xintong, according to BBC pundit Ken Doherty. The Rocket entered his World Snooker Championship semi-final tied at 4-4, but walked away down 12-4 in a dismal collapse.

While Zhao was unfazed during his first Crucible semi-final, O'Sullivan missed an array of shots he would typically expect to make. A host of mistakes handed a golden opportunity to his opponent, which the Cyclone took with both hands.

Speaking ahead of the final frame of the session, which O'Sullivan went on to lose, Doherty assessed the implosion: "We've seen Ronnie O'Sullivan does this to opponents, but now the shoe is on the other foot.

"Ronnie is probably a little bit embarrassed about what's happening out there. He's not fighting. He could have come to the table and played some snookers but is not bothering and that's worrying. It's a must-win last frame for him now."

Speaking earlier in the session, Doherty added: "Zhao Xintong almost looks born for this stage. The shots he is playing, he is making the game look so easy. He's getting help from Ronnie O'Sullivan, who is causing problems for himself by leaving easy chances to a player with a hot cue.

"Ronnie needs to scrap for these two frames. It's not his game but he has to do it. I'd never discount Ronnie, but he needs to get some frames on the board."

The pair will return on Friday evening for the second of their double-header and play to a finish.

BBC commentators John Virgo and John Parrott continued to laud Zhao for his efforts, while noting that O'Sullivan will be gutted to be on the receiving end of a Crucible session whitewash for just the fourth time ever.

Parrott said: "This has been absolutely brilliant from Zhao Xintong. We are used to giving the man sat in the chair the plaudits but this has been absolutely fabulous from Zhao. Ronnie has not been at the races but boy has Zhao played well."

Virgo added: "It's been absolutely wonderful from Zhao Xintong. Eight frames played and he's won all of them. Take a bow, Zhao. Ronnie O'Sullivan will have been impressed with that performance, but not with his own."

O'Sullivan had changed part of his cue, opting for a new titanium ferrul, after the opening session of the semi-final. However, multiple mis-cues may prompt the Rocket to reconsider that decision as he stares down the prospect of crashing out of the tournament.