Reigning champion Luke Littler worked hard for a 3-0 win over David Davies as Gerwyn Price was on the end of a shock second-round defeat at Alexandra Palace.
Davies came out and was playing an epic game in the first set, averaging over 103 in the early exchanges as he broke the world No 1's throw.
However, as Littler took the fourth leg following the Welshman missing six set darts, Davies was flummoxed and went to walk off the stage without realising the set was still alive, giving Littler the control to take out 82 on tops despite a low 89.04 average.
It was not long though until Littler's average was up over 96 and, after a sublime 145 checkout, he started to run away, picking up three legs on the spin to move one set from a third-round spot.
Davies' doubling was the element of his game that was letting him down and at one point, he had missed 16 doubles while Littler only had 16 chances at the double total.
While Littler got to wrap up the contest on his favourite 10 and did not drop a set, the match was anything but routine, with the Welshman pushing 'The Nuke'.
He now faces Mensur Suljovic in the third round as he looks to become the fourth player ever to go back-to-back.
Littler says Suljovic messaged him when the draw was confirmed to expect a meeting in round three.
"I'm happy with it, but just throughout that game I was getting away with it," Littler told Your Site.
"David missed 16 darts at a double, but every dart he missed was crucial - the double 18s, the tops.
"If he hit them, it was a complete different game, but I'm glad he missed. I've got the job done.
"I watched it this afternoon and Mensur [Suljovic] played well.
"Obviously, no one knows this, but when the tournament draw came out, Mensur messaged me, and he said 'see you in round three'.
"So, Mensur, let's have a good game."
Price was on the end of a demolition job from Wesley Plaisier as the Dutchman pulled off the biggest shock of the tournament so far and his "biggest victory ever".
The ninth seed exclaimed just days ago that he was going to win the Worlds, including a potential quarter-final against Luke Littler on the way, but could not find what he needed in the big moments of the match that saw Plaisier reach the third round on just his second-ever appearance at Ally Pally.
Plaisier came out fighting in the opening set and made having the darts count, breaking Price's throw in the fourth leg to go 1-0 ahead, his 60 per cent doubling success putting him on top.
The Dutchman did not drop his level in the second set either while the doubles started to elude Price, an early break of throw giving Plaisier the advantage before a clutch dart at D4 put him one set from a monumental upset.
Plaisier just kept the pressure on and, with the throw on his side in the third set, he kept control and took out D10 to seal the deal.
"I still cannot believe it, I am so over the moon," Plaisier told Your Site.
"This is my biggest victory ever I think. I don't know how I did it but I am happy I kept calm at the end.
"I was so nervous, I am so happy I got it over the line. I can't explain it in words, it is just so special.
"I thought I was going to give him a hell of a match, I did not expect to win it."
Elsewhere, 16th seed Damon Heta survived a scare as he was taken all the way by Stefan Bellmont but the Australian held firm to break the throw at the pivotal moment to set up a meeting with former champion Rob Cross after the Christmas break.
Meanwhile, Martin Schindler made his mark with a comprehensive 3-0 victory over Keane Barry, winning each of the sets 3-2 on legs with some clutch doubling and a 96.16 average.
Littler's next opponent Suljovic made it through to the last 32 of the World Championship as he defeated a visibly annoyed Joe Cullen 3-1 in a feisty encounter on Sunday afternoon.
The Austrian star averaged 82, hit three 180s and a high checkout of 100 in his victory but referee Kirk Bevans warned Suljovic to speed up the retrieval of his darts after over-celebrating on stage.
Cullen, nicknamed 'The Rockstar' was not happy with the veteran Austrian at the end of the match, accusing him of gamesmanship in a social media post.
Former world champion Rob Cross closed out a battling 3-1 victory over Ian White with a 91.71 average, 41 per cent on his doubles, three 180s and a 113 checkout.
Krzysztof Ratajski produced a strong performance to defeat Ryan Joyce 3-1 as the Pole reached the last 32 for the sixth time in his career.
He finished with a 94 average, hit three 180s and a high checkout of 135 to progress to the third round.
And Luke Woodhouse swept German Max Hopp aside in straight sets to set up a clash with Andrew Gilding.
The second round continues on Monday December 22 with two more bumper sessions of darts coming your way on Your Site.
From 12.30pm, you can catch, Darren Beveridge v Madars Razma, Wessel Nijman v Gabriel Clemens, David Munyua v Kevin Doets, and James Wade v Ricky Evans.
Then, from 7pm, Gian Van Veen takes on Alan Soutar, Nathan Aspinall plays Leonard Gates, Luke Humphries faces Paul Lim, and Charlie Manby is against Adam Sevada.
Who will win the Paddy Power World Darts Championship? Watch every match exclusively live all the way through until January 3 on Your Site' dedicated darts channel (Sky channel 407 from December 10). .
