Bradford (4) 14
Tries: Tadulala, Sykes, Nero Goal: Deacon
Harlequins (10) 22
Tries: Gafa, Esders, Howell 2 Goals: Orr 3
Harlequins snapped a run of six successive defeats and moved back into the play-off places with victory over Bradford at Grattan Stadium.
David Howell crossed twice in the last 15 minutes to deny the Bulls.
The Bulls twice led after an early Semi Tadulala try and later efforts from Paul Sykes and Chris Nero.
But earlier tries from Matt Gafa and Ryan Esders and Howell's late brace left the home side well out of the play-off race.
Tadulala pounced on a Sykes kick for the opening try after eight minutes but the home fans were stunned when Quins hit back with two tries around the half-hour mark.
Louie McCarthy-Scarsbrook was stopped just short of the line, but Danny Orr quickly sent the ball wide for Howell to set up Gafa before Esders, currently on loan from Hull KR, followed him over moments later from a Luke Gale pass.
Orr's conversion gave the visitors a 10-4 half-time lead but the Bulls levelled when Terry Newton created the gap for Sykes to run through and score. Paul Deacon converted.
The Bulls reclaimed the lead when Nero raced over in the corner after a break from Sykes and good support play from Deacon.
But Dorn's inside pass sent Howell over for his first and he added a second, after Chris Melling had raced 80m from in front of his own posts, to wrap up victory.
Bradford coach Steve McNamara:
"It was a tough game. Both teams fought very hard but there wasn't a great deal created by either side.
"Once we got ourselves in front we were probably in a position where we could push on with it but we did not quite manage to do that.
"That is way out of our control now. All we can do is stay mentally strong as a group, stay together right until the end and try win our remaining five games."
Harlequins coach Brian McDermott:
"It was a tight game and that was one you would have been relieved to win anyway, and not just because of the last six weeks.
"It has been a bit of an odd review in the last six weeks. We haven't been too down on what we have been producing.
"I have found it hard to stand in front of the players and say, 'You've done this wrong, that wrong and you're not up to it'. I couldn't do that because it would have been a lie.
"But there were things we haven't been doing well and we've been missing some men. This keeps things rolling a little bit but we have still got five games to go."
Bradford: Halley, Sheriffe, Menzies, Nero, Tadulala, Sykes, Deacon, Lynch, Godwin, Scruton, Whitehead, Morrison, Langley. Replacements: Newton, Kopczak, Donaldson, Worrincy.
Harlequins RL: Sharp, Wells, Gafa, Howell, Melling, Dorn, Gale, Temata, Orr, Ward, Williamson, Robinson, Golden. Replacements: Esders, McCarthy-Scarsbrook, Heckenberg, Kaye.
Referee: P Bentham (Warrington)