Chris Porter's brace helped play-off chasing Colchester beat Luton 2-1 and deal a blow to their opponents' Sky Bet League Two promotion hopes.
Colchester took a fourth-minute lead when Porter netted with a fine looping header from Brennan Dickenson's superb cross.
Luton keeper Matt Macey foiled Dickenson and Drey Wright while Tom Eastman headed over from six yards, as the U's pushed for a second.
Colchester eventually doubled their lead just after the half-hour mark through Porter, who prodded in Richard Brindley's cross from close range despite Macey's efforts to keep it out.
Porter almost completed a hat-trick just before half-time when he headed over from Sean Murray's free-kick.
Luton improved after the break and substitute James Justin's curling effort was palmed over by keeper Sam Walker, seconds after George Elokobi had cleared Alan Sheehan's shot off the line.
Luton gave themselves brief hope when Isaac Vassell scored from close range after Colchester had failed to clear a ball into the box but the hosts held on for a valuable win.