Harvey Rodgers' first-half strike secured a fifth straight League Two win for 10-man Grimsby as they edged past Colchester 1-0.
Both sides struck the woodwork in a tightly contested encounter, but it was the Mariners who held on after being reduced to 10 men in the second half.
Woodwork Denies Both Sides
Colchester went close in the 13th minute when Samson Tovide hit the woodwork at the near post after Will Goodwin had escaped down the right and picked him out.