De Zwaan stuns van Gerwen in huge shock on opening night of World Matchplay darts in Blackpool
Van Gerwen was odds-on to win the event but fellow Dutchman De Zwaan repeated his UK Open triumph of March with a stunning 10-6 victory.
With Van Gerwen not at his usual brilliant best, the exciting youngster took full advantage, firing in a game-changing 121 checkout to level the tie at 6-6.
Advertisement
Hide AdAdvertisement
Hide AdDe Zwaan then reeled off the next four legs to raise the roof at the Winter Gardens and set up a second round clash with Adrian Lewis.
"I am absolutely over the moon with this win," said De Zwaan, who was making his World Matchplay debut after winning a Players Championship event in April.
"I always believe in myself. I said to myself, 'Why can't I beat Michael? I know I am good enough to do it.'
"To win this game on this stage is an absolute dream for me. I have to keep pinching myself!
Advertisement
Hide AdAdvertisement
Hide Ad"Everything has come together for me recently. I'm practising hard every day and now it is paying off.
"I'm looking forward to playing Adrian on Tuesday and I want to cause another upset."
The opening match of the night saw 2013 finalist Lewis survive a scare as he overcame James Wilson 10-8 in a tense affair.
Lewis started well, taking the opening two legs before the Yorkshireman fought back to lead 7-3 thanks to some clinical double hitting.
Advertisement
Hide AdAdvertisement
Hide AdThe two-time World Champion dug deep to lead 9-8 before hitting a magnificent 116 finish - the highest of the match - to seal his place in the second round.
Lewis said: "I felt a bit nervous because I've not played on TV for seven months. When I was 7-3 down I knew I had to find something and I did that.
"James was fantastic in the first 10 legs. I didn't quite have my rhythm at times but I sped up towards the end and got the job done.
"I've been feeling the pressure in first round games all year, so it's a relief to get through and hopefully I can push on now."
Advertisement
Hide AdAdvertisement
Hide AdFour-time quarter-finalist Dave Chisnall ran out a comfortable 10-4 winner against Keegan Brown, growing in confidence after a tricky start.
Brown began brightly, leading 3-2 before Chisnall hit brilliant back-to-back checkouts of 148 and 147 to take the lead for the first time.
Although Brown levelled at 4-4, Chisnall continued his charge as the former Grand Slam of Darts finalist rattled off the next six legs without reply to seal his place in the last 16 for a sixth year in succession.
"It's never easy to play Keegan," said Chisnall. "The 148 was a big turning point because he was on a double and I think from then his head went down. I've got to play a lot better."
Advertisement
Hide AdAdvertisement
Hide AdThe final game of the evening saw Michael Smith see off World Matchplay debutant Jonny Clayton with a 10-6 win. Fresh from claiming the Shanghai Darts Masters title, Smith was made to work hard by the Welshman in a tight clash.
With Smith averaging 10 points more than Clayton and leading 7-6, the former World Youth Champion kicked on in the final three legs to set up an all-St Helens clash with Chisnall in round two.
"I kept letting Jonny back in and it was a bit of a struggle, but I'm still in," said Smith, the 2018 Premier League finalist. "I didn't play my best but I ground out the victory.
"After Michael van Gerwen lost, I went to give myself a little talking to. It's not opened up because I still had a game to play tonight and another game before I played Michael. I could only worry about Michael van Gerwen in the quarter-finals, so I had to stay focused."
Advertisement
Hide AdAdvertisement
Hide AdThe £500,000 tournament continues on Sunday with a double session, including two-time World Champion Gary Anderson beginning his final challenge against Stephen Bunting.
Anderson has now been installed as joint-favourite alongside Rob Cross at 4/1 with sponsors BetVictor.
SUNDAY'S FIRST-ROUND MATCHES:
Afternoon Session (1pm)
Darren Webster v Steve Lennon
Ian White v Max Hopp
Gerwyn Price v Joe Cullen
Daryl Gurney v Steve West
Evening Session (7.30pm)
Mensur Suljovic v Steve Beaton
Gary Anderson v Stephen Bunting
Rob Cross v Mervyn King
Raymond van Barneveld v Kyle Anderson