On-loan striker Tom Pope struck two second-half goals to give Port Vale a 2-1 victory which increases the pressure on Bradford boss Peter Taylor.
Rotherham man Pope squandered a great opportunity in the seventh minute when he headed wide from an excellent cross by Gary Roberts, before Doug Loft forced a smart save from Lenny Pidgeley.
But Vale's strong start soon fizzled out in a largely disappointing first-half, with the Bantams' best opportunity coming when Leon Osborne struck wide midway through the opening period.
It was a different story after the interval, though, as Pope headed his first in the 49th minute when he rose highest to bury Loft's right-wing corner.
And the points were almost in the bag for Vale when Pope fired in a 64th minute second after Justin Richards had flicked on an Adam Yates' cross.
Bradford reduced the arrears six minutes from time when Jake Speight set up Tom Adeyemi for a cool finish, but it proved too little too late.