World champion Mark Williams recovered from 3-0 down to defeat Jack Lisowksi 5-3 and reach the semi-finals of the Hong Rui Ma Yushan World Open in China.
Lisowksi dominated the early exchanges, with a century break in the third frame the highlight, but Williams pulled one back before the interval with a break of 96 and then benefited from a fluke on the last red to close the gap to one frame.
Englishman Lisowski missed a pink for a 4-2 lead, playing with his unfavoured right hand instead of the rest, and Williams made him pay.
Welshman Williams said on worldsnooker.com: "I just hung in there at 3-0 down because Jack was immaculate.
"He had an easy clearance to go 4-2 up then he played the pink right-handed. He might be really good right-handed but if he had got the rest out it was unmissable and then he probably would have won. He let me back into the match. I played well but I suppose he lost it rather than me winning it."
In the last four Williams will face Noppon Saengkham of Thailand, who defeated China's Xiao Guodong 5-1, while the other last-four clash will pit David Gilbert against Barry Hawkins.
Gilbert is through to only his second semi-final at a ranking event after beating Marco Fu 5-3, notching a break of 122 to go 4-1 ahead and then withstanding a Fu fightback.
Hawkins was the runner-up to Mark Selby at the China Open in April and is again showing strong form, moving through to the last four with a 5-3 victory over Gary Wilson.