Gerwyn Price was forced to draw on every bit of experience and composure in a sometimes fractious 10-7 win over Daryl Gurney.
Price's 114 checkout to level at 1-1 and a closing double 12 under pressure were the technical highlights, and his three-dart average of 97.9 edged Gurney’s 93.3.
Gurney had his moments, including a superb 150 checkout to stay in touch, but he was unable to shift the momentum.
Tempers then looked to boil over after Price's double 12 match dart finish, with Gurney apparently mocking the Iceman's trademark over-exuberant celebrations, which appeared to catch the Welshman's eye, before the pair exchanged a heated handshake before departing the stage.
Michael van Gerwen ensured his bid for a fourth Matchplay crown stayed on course by defeating Raymond van Barneveld 10-6 in a much-anticipated all-Dutch encounter.
While the match had its scrappy spells, MVG maintained control throughout, pulling away in the latter stages thanks to heavier scoring and more clinical finishing when it mattered, throwing five 180s and averaging 91.84 to Barney's 87.10.
"I was annoyed at my own game as I thought I could do better," Van Gerwen told Sky Sports.
"I think in only one leg he had the darts on the double before me and I should have taken advantage of that.
"When you make it difficult, it is a hard game. It was a really tough one for me.
"We all know this is a tournament I love to play - I have won it three times before, it is intense.
"We all know I am a winner, I don't like losing, I hate it.
"I think this could be the start of something really nice."
Earlier in the evening, Chris Dobey produced a composed performance to dispatch Ricardo Pietreczko 10-5. Dobey looked comfortable throughout, finding his scoring range early and holding his nerve on the outer ring.
The final encounter of the evening saw Northern Ireland's Josh Rock dispatch Ross Smith 10-5 after racing into a 5-0 lead out of the blocks.
Ross ended with an impressive 104.32 average and 45.45 per cent (10/22) on the doubles.
With six of the tournament's top 16 seeds already eliminated during the weekend, Monday's results offered a note of stability to a draw that still looks wide open.
The results conclude the first round of this year's World Matchplay, with Dobey up against Price and Van Gerwen taking on Rock in the second round.
Tuesday sees Gian van Veen facing compatriot Danny Noppert, Wessel Nijman versus Danny Noppert, Stephen Bunting against Gary Anderson and Jonny Clayton taking on Mike De Decker.
Follow the World Matchplay results and fixtures with Flashscore.