Luke Humphries moved into the quarter finals of the Boyle Sports World Grand Prix with a 3-1 win over Krzysztof Ratajski, as Stephen Bunting crashed out in Leicester.
Humphries - the 2023 champion and last year's runner-up at the Mattioli Arena - posted a 95.58 average and fired six maximums but was visibly frustrated at various points of a topsy-turvy contest.
The world No 1 needed a final-leg decider to open a two-set advantage and lost the next set to Ratajski, before Humphries burst into life by firing two ton-plus finishes to close out victory and build on his impressive record in the double-start event.
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Humphries now faces a last-eight meeting on Friday with Scotland's Cameron Menzies, who beat former world champion Rob Cross 3-1 earlier in the evening, while fourth seed Bunting also suffered a second-round exit after losing to Danny Noppert by the same margin.
The final match saw Gary Anderson roll back the years to thrash an out-of-sorts Joe Cullen in straight sets and book a quarter-final clash with Noppert, with the remaining four second-round matches being held on Thursday.
How Humphries survives stutter to book quarter-final spot
The top seed raced through the opening set in straight legs but squandered three darts to break throw again in the first leg of the second, where Ratajski missed four set darts in a final-leg decider before Humphries snatched a scrappy leg on double one.
A straight-sets win for Humphries looked a possibility when he opened with a 14-darter and produced his first 180 of the tournament in the next, only for Ratajski to hold throw and then win the next two legs to claim a set.
Humphries' stuttering finishing continued when he needed three attempts on the outer ring to close a 15-dart break at the start of the fourth set, but he fired a spectacular 132 checkout in the next and responded to a Ratajski hold by securing victory with a brilliant 104 finish.
The 30-year-old now plays Menzies, who survived two sets of darts in his opening set against Cross to take it in the final leg before breezing through the second in straight legs.
Cross started the third with a 107 finish and edged the set after his opponent missed five match darts to complete a 3-0 victory, but Menzies nailed a 136 checkout in the next leg and recovered from missing three more match darts to seal victory at the ninth attempt.
Bunting revealed on social media he was suffering from a sore back during his defeat to Noppert, where he battled back from two sets down to claim a clean sweep in the third set.
'The Bullet' followed a 68 finish with a sublime 125 checkout to take the fourth set to a deciding leg, where Noppert took out 100 in a two-dart combo to book his first quarter-final spot at this event in four years.
Anderson makes run to Leicester quarter-finals
A one-sided final match saw Cullen win just one leg and post a 68.05 average during a 3-0 loss to Anderson, who continues his impressive career by reaching a major ranking quarter-final on the PDC for a 17th consecutive calendar year.
"Joe [Cullen] was not at it tonight," Anderson told Sky Sports. "Playing against [James] Wade, he was really good. His starting tonight is what cost him - if he had kicked in a bit earlier I think I would have been on the ropes.
"My scoring came on at the end there. My finishing seemed to go in when I got a shot.
"It's getting harder and harder for me [to win events]. Same with Peter Wright and a few others, but we give it a try. Darts is a jolly for me now. I want to win. I'm going to try [and win more trophies]."
Who is playing on Thursday?
World No 2 Luke Littler headlines night four's action as he takes on defending champion Mike De Decker, having fired a 105 average during a thrilling victory against Gian van Veen in his tournament opener.
Three-time finalist Gerwyn Price plays Josh Rock and 2021 champion Jonny Clayton takes on Luke Woodhouse, while 2020 runner-up Dirk van Duijvenbode faces Daryl Gurney in the opening match of the evening.
Order of Play (Best of five sets)
Dirk van Duijvenbode vs Daryl Gurney
Jonny Clayton vs Luke Woodhouse
Luke Littler vs Mike De Decker
Gerwyn Price vs Josh Rock
The quarter-finals take place on Friday, with the semi-finals on Saturday then played over the best of nine sets. Sunday's final is the best of 11 sets, with the winner receiving the £120,000 first prize.
Watch day four of the Boyle Sports World Grand Prix live on Sky Sports+ and Sky Sports Main Event from 7pm on Wednesday, with coverage every day up to and including the final on Sunday. Stream darts, football, golf, cricket and more contract-free with NOW.
(c) Sky Sports 2025: World Grand Prix darts: Luke Humphries and Gary Anderson book quarter-final spots as Stephen Bunting crashes out in Leicester
