Report – bbc.co.uk
Three second-half goals from Swansea denied Tranmere a Carling Cup upset.
A Garry Monk mistake let Enoch Showunmi in, the striker showing composure to beat the keeper from a narrow angle.
Showunmi could have had three in a poor Swans first half, but a rocket from Andrea Orlandi hit the bar then struck Cedric van der Gun for the equaliser.
Shefki Kuqi set up Scott Sinclair whose superb control saw him beat the keeper, then Stephen Dobbie put in Kuqi for a close-range, last-minute strike.
The victory over the League One strugglers was Swansea's first on the road this season.