12 minutes later, the home side restored parity after Damien Delaney gave away a free kick outside the area. Boaz Myhill fumbled Craig James's effort, and Sam Collins put the rebound past him.
Stephen Brooker got the Valiants' second goal five minutes into the second half as they looked to take a foothold on the game.
Peter Taylor made an instant refreshment to his side by bringing on Ryan France followed by Jon Walters, and Delroy Facey was also brought on to make his Tigers debut.
It looked like Walters had earned City a late penalty when he was shoved in the box, but the referee turned down the shout.
Stuart Elliott finally got the equaliser in injury time from close range, but City threw the point away when Stephen Brooker struck again a minute later to earn Vale a 3-2 win.
City line-up (4-3-1-2): Myhill; Hinds (Facey 69), Cort, Delaney, Dawson; Green (France 51), Ashbee, Lewis; Barmby; Allsopp (Walters 54), Elliott.
Un-used subs: Duke, Joseph.