The opening exchanges of the second half were a somewhat different affair, with the Gunners seeing much more of the ball, though chances were at something of a premium.
Liverpool did need Kelleher to repel a powerful drive from Fabio Vieira towards the near post and the resulting corner was glanced off target by Gabriel midway through the half.
And, as the game ticked into its final knockings, Arne Slot opted to make seven further changes to his line-up, having already made three during the break.
Chasing a leveller, Eddie Nketiah rolled a low shot wide with seven minutes remaining, while Wataru Endo blocked well from Gabriel on the edge of the area.
Trey Nyoni broke only to see a shot saved by Hein in stoppage time, but Liverpool’s two first-half goals were enough to secure the win in Philadelphia over their Premier League rivals.
Liverpool: Kelleher, Szoboszlai (Blair, 71), Salah (Doak, 71), Jones (Endo, 46), Elliott (Morton, 71), Jota (Nyoni, 46), Tsimikas (Beck, 71), Carvalho (Bajcetic, 71) , Van den Berg (Phillips, 71), Quansah (Nallo, 71), Bradley (Stephenson, 46).
Unused substitutes: Jaros, Pitaluga, Davies, Konate, Gravenberch, Chambers, Gordon, McConnell, Koumas.
Attendance: 69,879