David Ngog’s early strike proved the only goal of the game as the Reds held on for the win despite Damien Plessis’ first half dismissal.
After a disappointing campaign last season, and a host of changes during the summer, new reserve manager John McMahon’s side have started well with two wins from three fixtures.
Ngog’s goal arrived after a huge clearance from David Martin – something he has no doubt learnt from Pepe Reina – and the French forward coolly headed past the United keeper.
The home side, playing at Tranmere’s Prenton Park, were in-control of the game before Plessis saw red after 34 minutes for a two-footed challenge.
Their were impressive performances from keeper Martin, defenders Daniel Ayala and new-signing Chris Mavinga, midfielder Victor Palsson and forward David Amoo.
Liverpool: David Martin, Stephen Darby, Steven Irwin, Daniel Ayala, Chris Mavinga, Victor Palsson, David Ngog (Nikola Saric 77), David Amoo (Emmanuel Mendy 71), Nathan Eccleston, Damien Plessis, Alex Kacaniklic (Jay Spearing 39)
Unused subs: Martin Hansen, Christopher Buchtmann