Arne Slot's new-look Liverpool beat Premier League rivals Arsenal 2-1 with goals from Mohamed Salah and Fabio Carvalho in Philadelphia.
Salah's 13th-minute strike and Carvalho's finish in the 34th minute capped excellent Liverpool moves, before Arsenal's Kai Havertz swept in a close-range shot in the 40th minute of an exciting first half.
Both teams made changes during the second half as the tempo dropped at Lincoln Financial Field, where the crowd of 69,679 marked a record at the stadium for a football match.
Liverpool have a final fixture in their US pre-season tour against Manchester United in Columbia on Saturday (00:45 BST Sunday).