Dave Chisnall produced an incredible fightback from 8-0 down to edge a thrilling Unibet Masters opener with Robert Thornton with a 10-9 triumph.
The Morecambe ace will now face Vincent van der Voort, who beat world champion Gary Anderson, in the last eight on Sunday as the quarter-finals, semi-finals and final take place at Arena MK in Milton Keynes.
Chisnall said: "Robert was playing well at the start and I missed a few doubles.
"I don't know what happened but I never gave in and I had nothing to lose.
"I thought I was going to lose because it's hard to come back from 8-0 down, but I took it leg by leg.
“He'd won eight legs in a row so there was no reason why I couldn't and he let me in.
"That's probably one of my best comebacks but I've got to improve on Sunday."
Thornton made an ideal start with a 14-dart finish, ending on tops, and then punished missed double from Chisnall in three successive legs by checking out 100, 78 and 80 as he took a 4-0 lead.
He then took out 122 to win the fifth - despite bursting his score on the same finish in the previous visit - punished further misses from Chisnall in leg six and took out 60 and 97 for an 8-0 advantage.
Chisnall finally got off the mark in leg nine, with his 15th dart at a double, before finishing 101 to continue his revival.
A pair of third-dart doubles - at tops and double 10 - saw Chisnall pull back to 8-6 before Thornton steadied his nerves with double 12 to claim his first leg in seven and edge 9-6 up.
The pair traded 180s in the 16th leg before Chisnall punished a missed match dart from the Scot to land double 16 and stay in the hunt, and double six then saw the resort thrower pull back to 9-8.
Chisnall's seventh 180 helped to set up double eight as he forced a decider, and when Thornton missed double top and 10 to close out victory, the world number 10 completed his amazing comeback by landing tops.