Andy Cook scored two goals in five first-half minutes as League Two Bradford knocked Championship side Hull City out of the Carabao Cup.
First Cook headed home before a corner was worked to him to score what proved to be the winner.
Hull, who made seven changes from Saturday's 0-0 draw at Preston, managed only two shots on target in the tie.
A moment of fortune helped the visitors take the lead midway through the first half as Randell Williams laid a ball on for Ozan Tufan 20 yards out.
Tufan's clean strike hit the bar and the rebound bounced in off unlucky Bradford goalkeeper Lewis.