Tranmere dictated for an hour against Port Vale but were then made to hang on from what in the closing moments of tgis LDV Trophy Northern Section second round game.
Vale did not manage a single shot on target in the first-half when Robin Hulbert fired over with their only chance.
Tranmere were ahead after only 6 minutes with Calvin Zola netting with an excellent left-foot shot from 12 yards when set up by Iain Hume.
Danny Harrison was only just wide midway through the half after a defensive error but the Merseysiders doubled their advantage in the 41st minute. Hume beat Jonathan Brain with a power strike from just inside the box after excellent build-up involving Paul Hall and Zola.
It needed a good save by Brain to Deny Stephen Jennings in the 56th minute and then Danny Harrison fired over.
Suddenly it was game on in the 68th minute when Christopher Birchall beat keeper John Achterberg with a snap 18 yard shot.
12 minutes later Achterberg had to be at his best to keep out an angled effort by substitute Darryl McMahon.
Then skipper Sam Collins put a freekick over before Michael Cummins in the 90th minute was only inches away from taking the tie into extra-time.
Hulbert and Craig James were best for Vale. Hume was outstanding for the winners.