Luke Humphries' defence of the BoyleSports World Grand Prix title continued with a battling 3-1 win over Jonny Clayton on Friday, as Ryan Joyce and Belgian duo Dimitri Van den Bergh and Mike De Decker joined him in the semi-finals.
A dramatic night of quarter-final action at Leicester's Mattioli Arena saw the event's final four players confirmed - with Humphries joined by two first-time World Grand Prix semi-finalists.
Reigning champion Humphries saw off 2021 winner Clayton in four sets, but overcame some nervy moments after the Welshman took a two-leg lead in the third.
A huge 149 checkout from Humphries saved the set, and he took he next two legs to move into a crucial 2-1 lead in the tie.
Clayton hit back from two legs down in set four, but was unable to pressure the world number one in the deciding leg as Humphries pinned double four to close out the win.
"That's probably the most nervous I've felt in a long, long time," admitted Humphries. "It's really not like me, but maybe I'm trying too hard.
"It was a really tough game. Jonny was unlucky there - he probably could have had the third set but that 146 changed everything.
"I feel really good and my game's in a good place so I won't take any negatives; I've won and that's it. I'll go into tomorrow in a confident mood - I know I can do it when it matters most."
Humphries now plays Ryan Joyce in the semi-finals on Saturday, after the Newcastle ace overcame former World Champion Rob Cross in five sets on Friday.
"Ryan will be looking forward to tomorrow, embracing and thinking that he's got nothing to lose," added Humphries.
"I feel very lucky that I'm still here but sometimes you've got to ride your luck. I prefer the longer format, so I'll be much more relaxed tomorrow.
"If I can perform like I can, it's going to be a tough game for Ryan but I know he's one of the best double 16 hitters in the world."
Joyce showed that accuracy on double 16 during a superb superb 3-2 win over number four seed Rob Cross, as the Newcastle ace reached just his second TV semi-final.
Cross made a superb start with a 14-darter and wrapped up the opening set with an 11-dart leg, only to see Joyce edge set two in a deciding leg and then land a 135 finish on his way to taking the third by a 3-1 margin.
Joyce took out a superb bull-bull-double 16 combination on 132 to open the fourth set, and tops loved him a leg away from victory before Cross took out 81 and 110 to tie the contest.
Cross also led in the decisive fifth set, but Joyce levelled and then punished misses from his opponent in the next two legs to capitalise and move into the last four.
Joyce finished 12 doubles from 19 attempts in a clinical display on the outer ring, and admitted: "It was a crazy match to play in - it's a great feeling to win.
"The match was topsy-turvy and every time I felt like I got ahead, Rob would throw a great leg. He's a class player.
"I always felt like this is the competition for me. I've played darts for so many years and I don't feel under pressure."
Humphries had defeated Joyce in his previous televised semi-final, at the 2023 Players Championship Finals, and he added: "Luke is not just a good player, he's maybe a generational player - but over this format I feel I can equal him and I'm going to try my best."
The other semi-final will be the first all-Belgian last four clash in a PDC Premier event after UK Open champion Van den Bergh and emerging star De Decker continued their best-ever World Grand Prix runs.
Van den Bergh came from a set down as he overcame some early wayward opening doubling in denying Joe Cullen a second successive semi-final in Leicester.
Cullen took the opening set in a deciding leg, with Van den Bergh finishing 118 in leg two but being punished for missing starting doubles in his opening two visits of leg five.
Van den Bergh then broke in the fourth leg of set two as a superb 11-darter saw him level the game as the Belgian found his range on the outer ring.
He took the third set by a 3-1 margin, aided by a 13-darter and a 90 finish on the bull, and repeated the feat in set four - taking out 109 for a 12-darter in leg three - as he booked a spot in the last four.
"My timing was key tonight but Joe didn't show how good he can be and in a few moments I stepped up," said Van den Bergh, who was aided by seven 180s.
"I wasn't feeling at my best but tomorrow I'm in the semi-finals and I'm going to give my opponent a game.
"Mike is on fire, he's doing strong stuff on a consistent basis and I need to be on top of my game - but I think I've give myself a boost.
"We've known each other a long time and we know that at the minute we're carrying the flag for Belgium, and I'm so proud of him and me. It's brilliant and I'm loving it."
De Decker won through to his first televised semi-final in style with a superb 3-0 win over two-time champion James Wade in Friday's opening tie.
All three sets went to a deciding leg in a high-quality contest, but it was the emerging Belgian who prevailed to continue his dream Leicester run.
Wade finished 106 and 105 for a pair of 12-darters as he led in set one, but De Decker followed up two 14-dart legs by taking out 66 in the set's decider to edge in front.
The Belgian also won the second set's deciding leg with a brilliant 122 checkout for a 12-darter of his own, and held throw to move to the brink of victory at 2-1 in set three.
Wade pinned tops for a 13-darter to keep his hopes alive, but De Decker was again first to a finish in the deciding leg, and double four sealed his progression to the last four.
"I'm buzzing - really, really happy," said De Decker, who hit 42% of his starting doubles and 50% of his darts at a finishing double.
"I've been doing it on the floor tournaments for the last two years and I'm bringing it to stage tournaments now.
"I maybe look relaxed but I'm really nervous. It's going well and at the right moments I'm doing the right things. Everything is going well."
Saturday's semi-finals will begin as Van den Bergh and De Decker clash, before Humphries takes on Joyce in the second encounter - with the format extending to the best of nine sets.
Humphries is now the 4/9 odds-on favourite with sponsors BoyleSports to win the title on Sunday night, with Van den Bergh the second favourite at 4/1 ahead of De Decker (11/2) and outsider Joyce (12/1).
The tournament is being broadcast live on Sky Sports in the UK, through the PDC's worldwide broadcast partners including DAZN and Viaplay, and on PDCTV (excluding subscribers based in the UK, Germany, Austria & Switzerland).
Click here for information on where to watch the 2024 BoyleSports World Grand Prix.
2024 BoyleSports World Grand Prix
Friday October 11
Quarter-Finals
Mike De Decker 3-0 James Wade (3-2, 3-2, 3-2)
Ryan Joyce 3-2 Rob Cross (1-3, 3-2, 3-1, 2-3, 3-1)
Luke Humphries 3-1 Jonny Clayton (3-1, 1-3, 3-2, 3-2)
Dimitri Van den Bergh 3-1 Joe Cullen (2-3, 3-1, 3-1, 3-1)
Saturday October 12 (2030 BST)
Semi-Finals
Mike De Decker v Dimitri Van den Bergh
Luke Humphries v Ryan Joyce
Sunday October 13 (2000 BST)
Final
Humphries/Joyce v De Decker/Van den Bergh
Format
Quarter-Finals - Best of five Sets
Semi-Finals - Best of nine Sets
Final - Best of 11 Sets
All Sets are the best of five Legs, with all Legs needing to both begin and end with a double.