A penalty converted by James Milner and Marko Grujic’s fierce hit from distance gave the Reds the kind of lead their first-half performance deserved at the interval.
Pedro Chirivella, one of 10 players introduced in the second period, quickly added to the scoreline with a straightforward rebound and Ben Woodburn sealed the win by earning and scoring another spot-kick.
The headline news in the starting line-up was the first appearance since February for Jordan Henderson in midfield, while the likes of Roberto Firmino, Milner, Daniel Sturridge and Georginio Wijnaldum began the game too.
There was little sign of rustiness from either side in the earliest exchanges and attacking intent was obvious in either direction, though more towards the Tranmere net.