John Higgins fought back from 3-0 down to edge out Mark Williams in a seven-frame nail-biter in the last-16 of the Northern Ireland Open in Belfast.
In what was the 40th meeting between Higgins and Williams, who both joined the circuit in 1992, the Scot moved 21-19 in front in the head-to-head count.
"I was one ball away from losing at 3-0 behind. Mark will be kicking himself," Higgins said.
"Mark has beaten me the last few times we have played so it was good to get a little one back on him."
Welshman Williams had to don a slipper after he claimed a dietary switch to vegetarianism saw him suffer with gout.
The three-time world champion said ahead of that match that a bout of gout had left him unable to put a shoe on his left foot.
Williams said: "A couple of weeks before it happened, for no reason I stopped eating meat and went on a vegetarian diet for a couple of weeks – and then I got gout!
"I'm feeling much better now. I can almost walk like normal. I’m on these tablets for it now.
"I have a slipper on my left foot. I cannot get a shoe on it. It’s too painful. I brought it over with me to Northern Ireland."
Judd Trump, winner of the last three Northern Ireland Opens, survived a scare to beat Jimmy Robertson 4-3.
Robertson had a chance to win the final-frame decider at the Waterfront Hall but a missed yellow cost him dear.
Trump told Eurosport: "I was 2-0 up again and I took my foot off the gas. The concentration isn’t quite there.
"I’m normally quite good that when I’ve got my man or woman on the ropes I put them away.
"But I’m not doing that at the moment and letting them back in the game way too easy. You get punished at this level and I nearly went out because of it."
Trump will face local favourite Mark Allen next, the Northern Irishman booking his quarter-final place with a 4-3 victory over Stephen Maguire.
In the late matches, David Gilbert stunned world number one Mark Selby 4-2, while Ricky Walden overcame a tough fight from Jackson Page to win 4-3.