
Playing the first of three Southern Section Group E games, the Pilgrims' starting line-up was completely changed from the 4-2 League One win away to Blackpool on Saturday.
Argyle opened the scoring in the 11th minute with a superb long-distance strike past Palace's Devon-born former Exeter City goalkeeper Harry Lee.
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Caleb Watts then netted in the 26th and 38th minutes to extend Argyle's lead to 3-0 at half-time, by which stage they had lost striker Owen Oseni to an ankle injury.
Donte Martin replied for Palace in the 57th minute but the Pilgrims responded with further goals from 17-year-old Seb Campbell and Bim Pepple.
Argyle will continue their Southern Section Group E schedule away to Newport County on October 6 before hosting Swindon Town on November 10.
Scroll below for all the latest updates from Chris Errington at Home Park:
New UpdatesKey EventsPepple makes it fiveView PostCampbell makes it 4-1View PostPalace pull one backView Post3-0 to ArgyleView PostArgyle aheadView Post22nd Sep20:55 BSTFull-time: Argyle Palace U21s 1Victory for Argyle in their first EFL Trophy group game with goals from Xavier Amaechi, Caleb Watts (2), 17-year-old Seb Campbell and Bim Pepple.