Former champions Judd Trump and Ding Junhui were dumped out in the last 16 on a day of shocks at the UK Championship in York.
Fifth seed Trump admitted he had simply not played well enough to beat world number 21 Joe Perry, who fought back from 3-1 down to clinch a 6-4 victory in style with a break of 136 in the final frame.
Trump told BBC Sport: "I didn't feel great the whole tournament and I played badly today.
"I just missed too many chances. Even though I didn't play well, I was still in control and should have used my experience and scraped through."
By contrast, Perry, who will face Tom Ford in the quarter-finals, was delighted with his performance.
Perry said: "He is a superb player, so I am chuffed to beat him. I am pleased with how I am playing. I am comfortable out there and I felt calm all the way through."
There was joy too for world number 59 Martin O'Donnell, whose 6-4 win over 2005 and 2009 champion Ding landed him a daunting last-eight showdown with Ronnie O'Sullivan.
The pair were locked together at 3-3, but O'Donnell, who had never been past the first round before, took the seventh and eighth frames, the latter with a break of 90, before clinching victory in the 10th.
He told Eurosport: "The UK Championship is the biggest tournament of the season, my record here has been absolutely appalling. [It's] definitely the biggest win of my career."
Asked about Friday's impending clash with O'Sullivan, O'Donnell told the BBC: "He could beat me 6-0, but I will enjoy it. If I get chances, I will have to take them. Let's see what happens."
Kyren Wilson made the last eight at the tournament for the first time after surging to a 6-2 win over Barry Hawkins.
The pair went into the mid-session break tied at 2-2, but it was Wilson who returned in dominant form, racking up breaks of 95, 78, 81 and 61 to win four successive frames.
He told Eurosport: "I feel like I belong in the top 16, I'm slowly creeping up on the top eight now and I feel like that's where the real elite is and I'm knocking on the door of that.
"There are many good players left in, but I'm not bad myself, so it's going to be an exciting tournament."
Wilson's reward with a quarter-final showdown with Stuart Bingham, who beat a luckless Sunny Akani 6-2.
Bingham led 4-0 at the interval with breaks of 117 and 81 in the first two frames and, although Akani pegged him back to 5-2 and might have reduced the deficit further had he not run out of position on the green in the eighth frame, edged his way home.