Goals from Omar Daley and Michael Boulding only hinted at the Bantams' supremacy against an out of sorts Gillingham. It was the first time the Kent club had lost back-to-back home games in the same season for two years.
Ground staff had to work hard to get the pitch playable after snow flurries earlier in the week, but the surface posed no problems and the game kicked off in weak sunshine.
The visitors immediately grasped the initiative and had three good chances to take the lead inside the first six minutes. Boulding had the best chance, but the striker headed just over.
Gillingham have grown used to dominating possession at home this season, but they struggled to impose themselves. With Curtis Weston suspended and Nicky Southall dropped to the bench, the final ball lacked quality.
Gills did have the ball in the net on 30 minutes, but Simeon Jackson's effort was ruled out for offside.
At the other end Simon Royce did well to parry efforts from Peter Thorne and Steve Jones, while Daley shot into the side netting from a good position. A minute before the interval he made amends, tapping home from eight yards after good work from Boulding.
The break did nothing to improve the hosts, who were lucky not to have skipper Adam Miller sent off for a crude challenge on Jones.
City looked increasingly assured and with 20 minutes remaining they made sure of a valuable away victory. Jones' speculative through ball looked innocuous enough, but it deceived Mark Bentley to send Boulding clear to score his 10th league goal of the season.
Gills boss Mark Stimson reshuffled his side late on, but it had little effect on a desperately disappointing performance.