Charles Vernam hit a superb hat-trick as Grimsby claimed an impressive 3-2 win at promotion-chasing Colchester.
Frank Nouble was denied by Grimsby goalkeeper James McKeown early on before Colchester went ahead in the 17th minute through Luke Prosser, who drilled a low shot into the bottom corner after a corner.
Town equalised four minutes later through Vernam, who scored with a fine right-foot shot from outside the box that sailed into the bottom corner after Matt Green's assist.
Vernam was denied by Colchester goalkeeper Dean Gerken soon after but Theo Robinson restored the hosts' lead in the 42nd minute when he stabbed home from close range after McKeown had only parried Ben Stevenson's low shot.
Grimsby levelled again in the 66th minute when Vernam swept home at the far post from Elliott Hewitt's cross.
And Vernam completed his hat-trick in sensational style three minutes later, dancing past several players before squeezing a low shot past Gerken to seal Grimsby's win.