Jamie Clarke's 25-yard strike helped Grimsby beat managerless Bury.
The visitors went close just after the half-hour mark when Nicky Adams found Richie Barker, whose close-range effort was well saved by keeper Phil Barnes.
But Bury were made to pay before the break when Clarke picked up a throw-in from Nick Heggarty, and turned inside to fire in off the far post.
Shakers substitute Simon Yeo should have levelled matters late on, but shot wide from a good position.
Grimsby: Barnes, Atkinson, Fenton, Newey, Hird (Bennett 84), Hegarty, Boshell, Hunt, Clarke, Jones, North (Taylor 88).
Subs Not Used: Montgomery, Bore, Til.
Goals: Clarke 40.
Bury: Provett, Haslam, Futcher, Scott, Woodthorpe, Stephens, Baker (Yeo 68), Buchanan, Barry-Murphy (Dorney 80), Adams, Bishop.
Subs Not Used: Challinor, Hurst, Mangan.
Ref: Graham Laws (Tyne & Wear).