Michael van Gerwen crashed out of the Ladbrokes UK Open at his first hurdle for the second year in a row - and defending champion Gary Anderson was also shocked on an incredible opening night in Minehead.
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World champion van Gerwen, who lost to Jeffrey de Zwaan in his opening match at the Butlin's Minehead Resort 12 months ago, was hot favourite to get his hands on this trophy for the first time since 2016 after making a superb start to the season.
But he entered the event at the fourth-round stage against Mervyn King on the back of a disappointing display in the Premier League Darts on Thursday night, resulting in his first defeat of the campaign against James Wade, and once again looked a shadow of his usual self during a 10-6 defeat.
You may not have thought that in the opening leg, however, as he produced a 170 checkout to delight the Main Stage crowd although King responded with 14 and 13 darters to edge ahead.
MVG, who won the season-opening Masters as well as the Players Championship One and Three tournaments after clinching his third world title on New Year's Day, restored parity but he soon found himself 5-2 down as King produced clinical darts to take advantage of his opponent's below-par display.
The world number one blew six darts at doubles in the next leg as the eight-time PDC tournament winner moved further ahead while he also took the next leg after MVG spurned dart at tops.
Van Gerwen began a mini revival with three legs on the spin, including an impressive 11 darter, before King capitalised on another missed double to go 8-5 up and then produced a stunning checkout of 141 for a 12-dart break of throw.
The Dutchman showed a glimpse of a revival with a 108 checkout for a 12-dart break of his own - after King missed his first match dart - but he was nowhere in the next leg as the Bradwell man sealed a famous win.
King averaged slightly less with 95.96 compared to MVG's 96.73 and hit just one of the three 180s in the match but his finishing was far better, pinning 10 of his 19 attempts as the Dutchman missed 13 of his.
It was also sweet revenge for the 52-year-old, who had lost his last seven meetings to MVG dating back to the 2014 Masters, because earlier this season at Players Championship Three he was branded a "disgrace to darts" by the two-time UK Open champion for "not even trying to beat me".
He certainly tried on this occasion.
"I fancied this right from the word go and it went my way tonight," said King, who made his UK Open debut in 2007. "My performance wasn't fantastic, I didn't play to the best of my ability by a long stretch but I just played better than Michael and took my chances.
"If I play at my best I believe there isn't a player here who can beat me, but there are so many players here capable of wiping you off the board if you're not at your best."
The "FA Cup of Darts", which had already seen 95 players bow out including Glen Durrant during the early rounds before the world's top 32 entered the competition in Friday night's fourth round, was blown further open when defending champion Anderson suffered a shock exit at the hands of Steve Beaton.
The Flying Scotsman, who lifted this prestigious trophy for the first time in his glittering career 12 months ago, was making his first appearance since losing to MVG in the World Championship semi-finals after a back problem had forced him to withdraw from the Premier League and all the other previous events until tonight.
Stats-wise he didn't seem too rusty as he averaged 100.17, hit seven 180s and pinned eight of his 14 attempts at doubles but Beaton produced his finest performance for some time on the big stage to win a number of key legs.
The Adonis has endured a poor run of results on the Pro Tour in 2019 but he appeared to be putting all that behind him when moving 4-2 up.
Anderson took the next three legs on the spin to edge ahead only for Beaton to level matters by taking out 80 before unleashing a 130 checkout to break his opponent's throw.
A 68 finish moved him further ahead and although Anderson pulled one back, the 54-year-old took out 100 for an 11-darter as he restored his two-leg lead.
The two-time world champion produced a mini turbo of his own to get back on level terms, with help from an 11-darter of his own after back-to-back 180s had threatened a perfect leg, but he didn't have another attempt at a double as Beaton claimed victory in their first meeting since he beat him to win the last of his PDC titles in 2017.
Beaton averaged 98.63 and although he only hit one maximum, he pinned 10 of his 19 double attempts and made three 100+ checkouts.
"My game is always in there, it just depends which Steve turns up on the day," said Beaton, who will celebrate his 55th birthday in April. "I didn't like the draw when it came out, but you've got to take every game as it comes and when it got to 5-5 I thought 'just go for it now' - I think it was an entertaining game for everyone.
"I play with the attitude that I will win if I produce a high 90s to 100 average but tomorrow's another day and I'll need to be at my best again."
Raymond van Barneveld also bid farewell to the UK Open for the last time as he suffered a 10-7 defeat to Simon Stevenson.
Barney has endured a poor start to his final season before retirement despite two heroic draws in the Premier League - in which he's still winless - and was always playing catchup as Stevenson stormed 8-3 clear.
The Dutchman, who averaged 94 compared to his opponent's 96 and missed 20 attempts at doubles, didn't give in but despite clawing himself back to 8-6 and 9-7 down, he'd given himself too much to do.
Rob Cross, Michael Smith, Gerwyn Price and James Wade are the players vying for favouritism to win their maiden UK Open titles as a result of MVG and Anderson crashing out.
Heading the betting at 5/1 is Cross after he thrashed Darren Webster 10-4 with a 99 average, five 180s and 50% checkout percentage.
The 2018 world champion will next meet King in a match he'll be expected to win - but that's what MVG thought.
Man of the moment Price, who won back-to-back Players Championship titles at the weekend and remains unbeaten in the Premier League, maintained his impressive form with a 10-6 victory over Joe Cullen.
Since becoming a major champion at the 2018 Grand Slam of Darts, Price struggled to deal with boos that stemmed from his actions in the final against Gary Anderson, which also resulted in a £21,500 and a three-month suspended sentence, but he's currently playing the best darts of his career.
He averaged 96 and three 180s but his highlight was a 156 checkout as he continues to turn those jeers into cheers.
Next up for Price is PDC newcomer Jamie Hughes, who came through all three early rounds with impressive averages before despatching Ian White 10-5 during the evening session.
The Tipton thrower was 300/1 pre-tournament but can now be backed at just 25/1 after underlining his credentials as a dark horse.
Price is 8/1 alongside Smith, who brushed aside John Henderson 10-5, and Wade, with the Machine thrashing James Wilson 10-1 a day after inflicting MVG's first defeat of the Premier League season.
Smith will face Daryl Gurney, who crushed Reece Robinson 10-1, in the fifth round while Wade takes on rising German star Max Hopp.
In the final match on the main stage, Mensur Suljovic defied Peter Wright's stunning average of 106 to triumph 10-8 in a pulsating clash in which the Austrian also hit a 170 checkout.
There was a dramatic finish in a thrilling clash between Jamie Lewis and Adrian Lewis on Stage Two, with the Welshman winning 10-9 thanks to a 161 checkout in the deciding leg.
Meanwhile Dave Chisnall, who was one of our outright tips at 40/1, is now 9/1 after he produced a fine comeback to defeat Luke Humphries 10-8 before being handed a draw with Martin Schindler.
Johnny Clayton and Nathan Aspinall, also backed pre-tournament alongside Chizzy, Price (20/1) and Cross (18/1) at 100/1 and 125/1 respectively, are also through after wins over Aaron Monk and Christian Kist.
Clayton has a tough fifth-round clash against Krzysztof Ratajski while Aspinall will next meet the dangerous Madars Razma.
Elsewhere Dimitri van den Bergh came through a dance off with Kirk Shepherd during the afternoon session before defeating him on the oche 6-0 and then defeated Ricky Evans 10-5 in the evening to set up a fifth-round test with Suljovic.
Saturday March 2
Afternoon Session (1230 start)
TV Coverage: ITV 4
(Best of 19 legs)
Main Stage
Stage Two
Stage Three
Stage Four
Friday March 1
Afternoon Session
First, Second & Third Rounds (Best of 11 legs)
Main Stage
Stage Two
Stage Three
Stage Four
Stage Five
Stage Six
Stage Seven
Stage Eight
Evening Session (7pm on Main Stage)
TV Coverage: ITV 4
Fourth Round (Best of 19 legs)
Stage Two
Stage Three
Stage Four
Stage Five
Stage Six
Stage Seven
Stage Eight
This round includes winners from the third round and the world's top 32 (scroll further down for full list)
Saturday March 2
Afternoon Session (1230 start)
TV Coverage: ITV 4
Fifth Round (Best of 19 legs)
Evening Session (1900 start)
TV Coverage: ITV 4
Sixth Round (Best of 19 legs)
Sunday March 3
Afternoon Session (1245 start)
TV Coverage: ITV 4
Quarter-Finals (Best of 19 legs)
Evening Session (19oo start)
TV Coverage: ITV 4
Click here for the full UK Open draw, tournament schedule and format