A 40th-minute goal from central defender Ian Goodison saw Tranmere safely through to the second round of the Carling Cup as they won 1-0 at Walsall.
Goodison finished from close range when Joss Labadie headed a free-kick from Paul McLaren across the face of goal.
Walsall, who sold their top striker Troy Deeney to Watford for £500,000 last week, only had themselves to blame for failing to progress beyond the first round of the competition for four years.
Poor finishing let them down and handed them their second home defeat in four days. Steve Jones shot straight at Tranmere keeper Joe Collister on seven minutes and in the 35th minute Aaron Lescott set up Julian Gray inside the box but the winger chipped straight in to Collister's grateful hands.
It was the same story in the second half, Walsall skipper Darren Byfield taking advantage of a Tranmere mix-up with a free-kick and sprinting half the length of the field before setting up Alex Nicholls who should have scored but Collister managed to block his shot from close in.
Tranmere could have settled the issue in the 52nd minute but Nick Wood ran in unmarked to meet McLaren's corner only to head over the bar.