Simon Whitlock claimed what he described as his best-ever victory to end Michael van Gerwen's hopes at the BoyleSports Grand Slam of Darts, as Dimitri Van den Bergh, James Wade and Jose De Sousa also reached the semi-finals in an epic Sunday.
An incredible day of quarter-final action saw 121 out of a possible 124 legs played across four gripping contests, with two going all the way to a sudden-death 31st leg.
Whitlock's gutsy 16-15 triumph over Van Gerwen means that a new name will be engraved on the Eric Bristow Trophy following the event, with all four semi-finalists now aiming to take the title for the first time on Tuesday.
Australian star Whitlock picked up his third successive televised win over Van Gerwen this year in the most dramatic circumstances, surviving eight missed match darts from the world number one.
Three-time champion Van Gerwen had led 2-0, 9-5 and 11-7, with Whitlock pulling back to 13-all before a stunning 146 checkout looked to have broken his resistance as the Dutchman moved 15-13 up.
Van Gerwen, though, missed three match darts as Whitlock saved the game on double 13, before hitting a record-breaking 19th 180 as double ten sent the tie into a deciding leg.
Whitlock opened the final leg with his 20th maximum, but Van Gerwen was first to a double - only to squander five further match darts and allow his rival to complete the fightback on double eight.
WHITLOCK WINS A CLASSIC— PDC Darts (@OfficialPDC) November 22, 2020
An instant Grand Slam of Darts classic! Simon Whitlock not only hits a tournament record 20 180s but he also clinches a spot in the semi-finals with a dramatic deciding leg victory!
When that D8 went in, it was the first time he lead in the entire match! pic.twitter.com/diovmidJ1u
"I feel on top of the world," said Whitlock. "It's incredible - I think this is my best victory I've ever had in darts.
"To beat Michael when he's off his game is another thing, but to beat him when he's playing well - which I thought he did today - is amazing.
"This is becoming a nice habit - I've won three on the trot now but I'm playing good darts now.
"I was enjoying the moment but I didn't expect to get a shot. I was thinking it was all over but somehow he missed and gave me a chance, and I took it.
"I showed belief, guts and determination. The only time I was in front was when I hit the winning double - it's crazy."
In the first of tonight's semi-finals, Whitlock will play De Sousa, who continued his history-making week by out-lasting Michael Smith 16-14 in another sensational tie at Coventry's Ricoh Arena.
De Sousa becomes the first Portuguese player to win through to a televised semi-final after picking up what he admitted was the biggest win of his career.
Wade remains on course to reach his third Grand Slam of Darts final after taking a 16-13 win over Damon Heta in another high-quality last eight encounter.
VAN DEN BERGH WINS!— PDC Darts (@OfficialPDC) November 22, 2020
Dimitri Van den Bergh produces a magnificent leg in the decider to come out on top of an epic! pic.twitter.com/rrDqRlKvhe
Van den Bergh edged out Nathan Aspinall 16-15 in a final-leg shoot-out as he continued his bid to follow up July's World Matchplay triumph with another huge title.
Aspinall played his part in another epic contest, leading 11-8 at one stage and coming from 14-12 down to lead 15-14, only for Van den Bergh to finish the stronger and claim the game's final two legs.
"I'm so chuffed that I'm through," said Van den Bergh, who now plays Wade. "It was a proper emotional rollercoaster and I'm still in that ride.
"I kept battling and never gave up because today was a such a struggle. I lost the first three sessions 3-2 and went down 9-6, but I kept digging in and believing in myself.
"We didn't perform the way we can but at least I have a chance to improve in the next round, and I will learn from this quarter-final. It's a lesson for me but this week is going very well and I'm playing strong."