Mansfield's eight-game unbeaten run came to a shuddering halt as struggling visitors Hartlepool put them to the sword 4-1 at the One Call Stadium, where the Stags had previously lost just once in league action in 2013.
Mansfield made a bright enough start, Ryan Tafazolli heading against the post and sending the follow-up wide after six minutes, then Calvin Andrew's diving header flew just wide a minute later.
But the visitors rocked the Stags with an unstoppable blast from 25 yards from Andy Monkhouse in the seventh minute.
The goal visibly lifted Hartlepool, who went on to dominate the first half.
Stags changed from 3-5-2 to 4-4-2 after 24 minutes, but it made little difference as goalkeeper Alan Marriott remained the busier keeper and had to save well from Jack Compton's 22nd-minute shot.
A minute from the break, the visitors deservedly doubled their lead, Compton cutting in from the right and firing low shot under the dive of Marriott, who looked to be late getting down.
The Stags made a double change up front at the break, but were picking the ball out the net again within five minutes as Compton curled in a 20-yard free-kick over the wall and inside the post.
Sam Clucas did give the toiling home side some hope with 15 minutes to go with a low penalty conversion after Pools defender Sam Collins was adjudged to have handled Matt Rhead's overhead shot.
But Pools wrapped up a fine afternoon four minutes later when two-goal Compton turned creator as he set up James Poole for a firm low 20-yard finish to seal only their second win of the campaign.