Defending champion Jonny Clayton was taken the distance in his opening match at the World Grand Prix, eventually edging past Dirk van Duijivenbode 2-1.
Clayton made an ideal start to the match, hitting double 16 with his first dart, but the same bed eluded him as he lost the opening leg despite throwing first.
Eight missed darts at double at the beginning of leg two allowed in-form van Duijvenbode to cruise to the opening set and Clayton was in trouble when losing the opening leg of set two.
Clayton levelled with a tidy leg and then broke throw with a 130 checkout to change the course of the match as van Duijvenbode began to struggle to hit his opening doubles, missing 13 such darts during the second set which Clayton took.
By now the momentum was with the Welshman and after the pair exchanged breaks of throw in the final set, it was Clayton who found a decisive second break to seal a 2-1 victory.
“I’m glad to get through obviously, but Dirk should have won that game,” conceded Clayton, who defeated Gerwyn Price in last year’s showpiece.
“I just couldn’t get going tonight, but thankfully I managed to scrape through.”
Next for Clayton is a Wednesday clash with Dimitri Van den Bergh, who also came through a stern test of his credentials to beat Dave Chisnall 2-1.
Chisnall forced a deciding set by taking the second but Van den Bergh had the darts and the answers, a 13-dart leg sealing a deserved victory.
Michael van Gerwen – chasing a sixth World Grand Prix success – ran out a resounding 2-0 winner against two-time world champion Gary Anderson in a repeat of the 2016 final.
The Dutchman reeled off a scrappy first set without reply, despite Anderson missing darts to win every leg - squandering 11 darts at double in total.
The Scot responded with a clinical 84 kill to seize control of the second set, but after firing back with a 15-dart riposte, Van Gerwen followed up his third 180 with a 106 finish to seal the deal in 12 darts.
“The first round at the World Grand Prix against Gary Anderson is never going to be easy,” admitted Van Gerwen, who averaged 101 in a superb second set display.
“You never know with Gary. He still has a lot of talent and is a brilliant player, so you have to perform well.
“We both missed so many doubles in the first set, but the second set is something to build on for the next round.”
Earlier, Chris Dobey stunned Luke Humphries to cause an early upset, winning five legs in a row to seal a 2-0 victory.
Dobey was 2-0 down in the first set but Humphries let him in with nine missed darts at double to begin leg three, and from there Dobey won every leg to run out a commanding winner.
He'll play Adrian Lewis next, after the 2010 finalist made a winning return in his first World Grand Prix appearance since 2019, converting three ton-plus checkouts to close out an impressive 2-0 win over Jose De Sousa, who becomes the first seed to exit this year’s tournament.
Lewis took out 152 and 101 to claim the first set, and a brilliant 147 finish sparked his revival in the second, as he reeled off three straight legs to prevail.
Krzysztof Ratajski and Stephen Bunting were also 2-0 winners against Callan Rydz and Brendan Dolan respectively, while Peter Wright beat Kim Huybrechts by the same scoreline.
Huybrechts hit his opening double in each the first five legs but had problems at the other end and was made to pay by Wright – at least until the latter missed two match darts when in command of the second set.
That sparked something in the Belgian, who took out 128 on the bull to keep his fading hopes alive and then 101 to force a deciding leg, where he missed a dart at tops for a third straight 100-plus finish which would've forced a third set.
That allowed Wright in to hit double nine and finally end the match with his fourth attempt, the 2-0 scoreline perhaps a little harsh on Huybrechts.
Monday October 3 (7pm)
TV Coverage: Sky Sports
First Round (Best of three sets)
Tuesday October 4 (7pm)
TV Coverage: Sky Sports
First Round (Best of three sets)
Wednesday October 5 (7pm)
TV Coverage: Sky Sports
Second Round (Best of five sets)
Thursday October 6 (7pm)
TV Coverage: Sky Sports
Second Round (Best of five sets)
Friday October 7 (7pm)
TV Coverage: Sky Sports
Quarter-Finals (Best of five sets)
Saturday October 8 (7pm)
TV Coverage: Sky Sports
Semi-Finals (Best of seven sets)
Sunday October 9 (7pm)
TV Coverage: Sky Sports
Final (Best of nine sets)