Wayne Mardle recovered from losing the first three sets to beat 13-time world champion Phil Taylor and reach the PDC World Championship semi-finals.
Taylor led 3-0 before Mardle fought back to win 5-4
Taylor had needed a deciding set in his three previous matches but this time Mardle came through, winning 5-4 by taking the 10th leg of the decider.
In the semi-finals Mardle will face Kirk Shepherd, who earlier sent veteran Peter Manley crashing out.
John Part beat James Wade 5-4 and meets Kevin Painter in the last four.
Painter won Saturday's last quarter-final 5-2 against Adrian Lewis.
Shepherd, a 21-year-old qualifier, had already beaten three seeded players and said: "I can't believe it.
If Wayne gets his head on now he's got the best chance of his life to be world champion
"I don't mind who I play next, I'm on a roll and I just want to keep going."
Canadian Part will take on either Painter, who stunned 2006 champion Raymond van Barneveld in the last 16, or seventh seed Lewis for a place in the final.
Taylor has had to battle hard to reach the latter stages and was nowhere near his best but Mardle was in even worse touch as he dropped the first three sets.
But Mardle suddenly burst into life in the fourth and stormed back to level, sending the crowd wild.
Taylor moved ahead again before Mardle levelled at 4-4 and repeatedly pegged the ex-champion back in the decider, before breaking in the ninth leg and sealing a famous victory in the next.
"He played brilliantly, he stuck in well," said Taylor. "Fair play to the lad, he was brilliant in the final few legs.
"If Wayne gets his head on now he's got the best chance of his life to be world champion."
Mardle said: "Everyone has said that he (Taylor) has played badly all week, but it takes a great game from me to beat him.
"I felt fantastically good and I kept saying to my family 'don't worry, I'll win'. I won't let anyone down whether I win or not.
"I will not give up. I was 3-0 down and felt I could win and I did."