Emile Sinclair scored the only goal as Crawley extended their unbeaten league run to seven games by beating Bradford.
Bantams midfielder Mark Thompson should have put the visitors ahead in the first half, but wastefully shot over.
And Sinclair put Crawley into the lead after the break when he raced on to Andy Drury's pass and slid a neat finish under keeper Jon McLaughlin.
Drury then struck the top of the bar with a cross before Paul Jones saved brilliantly from Bradford's Kyel Reid.
VIEW FROM THE DRESSING ROOM
Crawley Town manager Richie Barker told BBC Sussex:
"As an all-round performance, that was one of our best this season. [Goalkeeper] Paul Jones didn't have a lot to do, but what he did do was excellent.
"To be fair to Bradford, they probably caught us a bit cold. It was a surprise considering we knew what was coming at us, but for some reason we didn't look quite at it.
"We rode the storm a bit and I have to say our defending in the last 15 minutes was absolutely fantastic. It's a fantastic win and I can't speak highly enough of the players."
Crawley Town 01 Jones 11 Simpson 03 Sadler 21 Jones 05 McFadzean 12 Walsh 10 Drury 15 Bulman Booked 20 Sinclair (Alexander - 79' ) 14 Proctor (Connolly - 88' ) 16 Adams (Essam - 93' ) Substitutes 04 Connolly 06 Essam 08 Torres 09 Alexander 18 Rooney 25 Maddison Bradford City 01 McLaughlan 02 Darby 03 Meredith 24 Doyle 23 McArdle 22 Bates (Connell - 76' ) 11 Thompson (De Vita - 72' ) 18 Jones 09 Hanson 14 Yeates (Folan - 64' ) 07 Reid Substitutes 06 Oliver 08 Kennedy 12 Ripley 16 McHugh 17 Connell 19 Folan 20 De Vita
Ref: Dean Whitestone