Colchester claimed a first-ever win over Crawley with a deserved 3-1 victory at the Weston Homes Community Stadium.
The U's took a ninth-minute lead when Sammie Szmodics superbly volleyed home from Ryan Jackson's cross.
And Colchester went further ahead five minutes later when Jackson slammed the ball past goalkeeper Glenn Morris after excellent play by Szmodics had set him up.
The home side made it 3-0 seven minutes before half-time through Mikael Mandron, who nodded in from two yards after Frankie Kent had headed Brandon Comley's cross back across goal.
Tom Eastman and Ryan Inniss combined to clear Panutche Camara's shot off the line before the break, while Crawley squandered the chance to get back into the game in the 52nd minute when Walker saved Mark Randall's penalty after debutant Inniss had fouled Josh Yorwerth in the area.
Jimmy Smith poked home from a corner in a crowded area midway through the second half to give Crawley hope and Walker denied Smith late on, but it was Colchester's day.