Tom Pope, Ben Williamson and Billy Knott scored but keeper Chris Neal was stretchered off in a dramatic five goal thriller at Vale Park.
Micky Adams brought back Anthony Griffith to replace the suspended Chris Lines as the Vale roared into an early lead. Tom Pope fed Jennison Myrie-Williams and Pope was on hand to convert his fifteenth of the season with just three minutes played.
The visitors rallied with a goal disallowed for offside and several chances for the dangerous Ryan Lowe. But Vale also had chances with Pope and Grimmer having headers from corners as the first-half drew to a close.
The second-half started as the first with Vale scoring early on. On 47 minutes, Ben Williamson fed loanee Billy Knott for an excellent first Vale goal. That goal inspired Vale and the side created several chances to increase their lead.
But it didn’t take long for Vale to stretch their advantage. On 56 minutes Ben Williamson scored his fourth in four games after being set up by Pope.
That looked like game over but three minutes later, Tranmere got a goal back as Ash Taylor netted and sixty seconds later, the visitors were right back in it as Rovers made it 2-3 through Jason Koumas. With half an hour to go, the game could now go either way.
Vale nearly sealed the win when Doug Loft rattled the crossbar with fifteen minutes left and more good play set up Pope only for the striker to miss the target.
But after that good play, there was a huge blow for the Valiants as Chris Neal was challenged by Goodison and the popular Vale keeper was stretchered off to be replaced by Sam Johnson.
Johnson was called into action almost immediately as Tranmere tried to draw level while Pope was denied during a one-on-one chance with the Rovers keeper.
But despite drama at both ends of the pitch and seven minutes of injury time, the Vale managed to hold on to secure an important three points after yet another dramatic ninety minutes at Vale Park.
Vale: Neal (Johnson), Yates, Grimmer, Duffy, Dickinson, Myrie-Williams (Birchall), Griffith, Knott, Loft, Williamson (Hugill), Pope
Subs: Jones, Dodds, Tomlin, Robertson
Attendance: 5,449 (670 away)