Scotland's Graeme Dott defeated fellow Scot John Higgins to complete the quarter final line-up at the Embassy World Snooker Championships.
Underdog Dott won the clash 13-10 but afterwards admitted: "I'm not really in the same league," referring to his opponent and former champion.
Dott has been second best in all but one of their previous meetings, so victory was particularly sweet for the Larkhall-based professional.
Higgins, world champion six years ago, briefly threatened to pull off a great escape as he won three successive frames from 12-7 down. But Dott produced a superb 62 break in frame 23 to set up a meeting with another surprise first-time Sheffield quarter-finalist David Gray.
"I know I can beat any player in the world but I need a little bit of help," said the world number 13 after avenging last season's 13-2 defeat at the same stage of the tournament.
"I couldn't play to that standard John produced last year, probably even in practice. That's the worst I've seen John play. But to be honest, I needed him not to be on top form to beat him.
World number four Higgins is the highest seed to fall but he gave it his best shot after slumping five frames behind. He was on his way to a third maximum break of the season in frame 20 but broke down on the 12th black.
Higgins admits that in order to be a winner again he may seek the advice of a sports psychologist.
"My concentration is just not there," he said. "It's not good enough if I want to compete and win things. The more you lose the more you doubt yourself. It was torture out there, and it's heartbreaking when you play like that.
"Graeme is never going to blow you off the table but he did a fantastic break in the last frame when the pressure was on."