Matt Tubbs scored the only goal of the game as Crawley beat Hull in round four of the FA Cup on Saturday afternoon.
Crawley, who are enjoying a productive season in League Two, might have taken the lead after three minutes when Kyle McFadzean struck towards goal, but it drifted just high of the crossbar.
The away side continued to make the early running and on-loan Arsenal star Sanchez Watt brought a fine save from Vito Mannone after 15 minutes.
Hull's best chance of the opening half came courtesy of a fine cross from Tom Cairney, but Liam Cooper could not convert his header from inside the area.
Cairney was again involved just before the break when he fired in a powerful effort from outside the area, but Crawley goalkeeper Scott Shearer pushed the ball to safety before making a fine save to deny Robbie Brady.
A goalmouth scramble almost led to the opening goal of the match after 50 minutes, but Joe Dudgeon and Aaron McLean both blocked shots from Crawley pair Claude Davis and Pablo Mills.
Crawley eventually broke the deadlock after 57 minutes when Tubbs finished coolly under the body of Mannone after good work from Sergio Torres.
Mills stood strong in the face of continued pressure from the home side in the latter stages, with Danny East beginning to influence the play.
Hull resume domestic duties against Doncaster on Tuesday, while Crawley travel to Bradford on Saturday.