Grimsby were brought back down to earth with a bump as Bristol Rovers secured a narrow win at Blundell Park.
The Mariners, who knocked Manchester United out of the Carabao Cup on penalties in midweek, were beaten for the first time this season by Macauley Southam-Hales' first-half goal.
The hosts struck a post early in the contest through full-back Reece Staunton's sweetly-struck free-kick.
But Rovers took the lead in the 27th minute when Southam-Hales' superb volley from outside the box flew low past goalkeeper Christy Pym after the ball had been headed out from a corner.
Pym came off his line to save at close quarters to stop Promise Omochere doubling the visitors' lead on the hour.
Another free-kick from Staunton went agonisingly wide, and Evan Khouri had a goal-bound effort diverted wide late on as Rovers defended well to register a first away league win since January.
Report supplied by PA Media.
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