Wales' Matthew Stevens took a nervy deciding frame to knock out defending champion Ronnie O'Sullivan 4-3 in the third round of the Welsh Open.
Five-time world champion O'Sullivan raced into a 2-0 lead at Cardiff's Motorpoint Arena, before Stevens edged a scrappy third frame and then levelled the match with a break of 80.
World number two O'Sullivan retook the lead with a clearance of 57.
But Stevens held his nerve to earn his first win over O'Sullivan for 12 years.
Stevens will play world number 11 Marco Fu in the last 16, after the Hong Kong player beat Ashley Carty 4-2 later in the day.
Current world champion Mark Selby came through his third-round match 4-3 against former world champion Peter Ebdon, while Australia's Neil Robertson saw off England's Jamie Cope 4-3.
England's world number six Judd Trump came safely through, as did Scotland's Stephen Maguire, both 4-2 victors - over Sam Baird and Michael Wasley respectively.
Michael Georgiou, conqueror of Wales' Lee Walker on Tuesday, added the scalp of former world champion Graeme Dott, prevailing 4-3.
The evening session saw former world champion Mark Williams victorious in an all-Welsh clash, beating Jamie Jones 4-2 to go into the fourth round.
Williams later criticised tables at the tournament and said the problem had existed "for years" at top tournaments.
"It was just making us look stupid at times and it was very hard to control the white," said Williams.
"Kicks - you get them all the time. But the bounces, we shouldn't be getting them now."
Another Welshman, Michael White fell to a 4-1 loss to England's Stuart Bingham in the third round.
Two-time World Championship runner-up Stevens said he would not get "carried away" with the win over O'Sullivan.
"The standard wasn't that good, but I don't care," he said. "I'm in the next round so it doesn't matter.
"I enjoyed being out there. Playing against Ronnie there's always a full house and especially in Wales it was a nice occasion."
The 37-year-old won the last three frames to come through his first-round match against world number 82 Oliver Lines before beating world number 38 Ken Doherty 4-3 in round two.
"I don't look past the first round," continued the 2003 UK champion. "It's the best of seven, they are all good players these days.
"I should have lost my first-round match. I was 3-1 down. So I'm not going to get carried away, I'm only in the last 16."