Celtic, playing their second match in three days, offered little resistance at Connecticut's Rentschler Field.
Liverpool went in front after four minutes thanks to John Arne Riise before England striker Michael Owen added a second goal on 17.
Former AJ Auxerre marksman Cisse, leading scorer in the French Ligue 1 last season, found the net twice in the second half while Swiss international Stephane Henchoz notched his first goal in more than five years with Liverpool.
Craig Beattie replied from the penalty spot for Celtic.
It was the second consecutive defeat for Celtic, who lost their tour opener 4-2 to Chelsea in Seattle on Saturday.
The series features 11 friendly matches at eight venues across the U.S., involving club sides from England, Italy, Scotland, Portugal, Germany and Turkey.
The next match is on Wednesday with Celtic taking on Manchester United in Philadelphia.