The young Reds, who rounded off their Premier League 2 campaign with a 2-1 win at Everton on Monday, took on their counterparts from Field Mill at the Academy.
Mike Garrity made wholesale changes from that mini-derby triumph at Goodison Park but Gomes’ treble, which came after Lloyd Jones’ first-half opener, ensured the hosts ran out comfortable winners.
Defender Jones, back at the club following his season-long loan at Swindon Town, headed Liverpool into the lead from a corner by Cameron Brannagan.
Their advantage was doubled before the break when Brannagan, who returned from his loan spell at Fleetwood Town after their elimination from the League One play-offs on Sunday, hit the crossbar with a free-kick and Gomes converted the rebound.