Second-half goals from Corey Whelan and Shaun Miller earned Crewe their second win in three games as the Railwaymen saw off Grimsby.
On-loan Liverpool defender Whelan's cool finish ended the resistance of Grimsby goalkeeper James McKeown, who had made a string of smart saves to keep the Mariners in the game.
Whelan stepped inside on to Charlie Kirk's cross-field ball to find McKeown's far corner in the 70th minute.
Striker Miller then registered for the first time since his return to Crewe on a permanent basis in the summer, glancing home Ryan Wintle's cross.
McKeown kept out Miller's early strike with his knees and smothered Kirk's close-range effort at the far post before saving the follow-up from James Jones.
Grimsby were not short of a threat, but their finishing failed to match their approach play.
JJ Hooper side-footed straight at Crewe keeper Ben Garratt and Wes Thomas broke clear but then buried his shot into the side-netting.
Hooper was denied by an instinctive save from Garratt, who also pushed around Charles Vernam's angled shot after the break.
McKeown excelled again thwarting Jordan Bowery, but he was finally beaten by Whelan and Miller, before he tipped Callum Ainley's late effort on to the bar.
Report supplied by Press Association.
