Grand Slam quarter-finalist Menzies was crestfallen after suffering a surprise defeat to veteran Gates.
The 54-year-old never looked back after hitting a 138 checkout in the opening leg against the Scot, who made the last four of the WDF World Championship in 2022.
While Gates wiggled his hips after nailing doubles, and was backed by chants of ‘USA, USA’, his opponent faced jeers and looked increasingly despondent as the match progressed.
Menzies, whose partner Fallon Sherrock plays Ryan Meikle on Tuesday, took deep breaths and appeared to wipe away tears between throws in the latter stages.
“I was definitely aware of it [his emotions],” said Gates. “But at the same time, I want my opponent to play their best against me to see if I can play my best against them.
“I told him to use the energy of the crowd, keep coming and keep playing the best he can to grow the PDC.”
Gates will now face two-time major winner Nathan Aspinall on Wednesday in the second round.
Before Price’s headline act, another Welsh win on night two was provided by Robert Owen, who came from behind to clinch a 3-1 victory over Dutchman Niels Zonneveld with a 121 checkout.
Owen’s first Ally Pally win sets up a second-round match on Thursday against German Gabriel Clemens, a semi-finalist in 2023.
England’s Scutt, a quarter-finalist at the Players Championship, encouraged the crowd to get behind him and gave them a show with a 101.92 average and 56% checkout success.
Nicknamed ‘The Sniper’, Scutt finished top of the secondary Challenge Tour order of merit and dominated Robb, of New Zealand, who has now lost all five of his World Championship matches.
Scutt, 28, faces Australian number one Damon Heta in the second round on Saturday, when teenage prodigy Luke Littler will also play his first match of the tournament.
