Sam Clucas stung his old club with a goal direct from a corner as Lincoln completed a double over Mansfield with victory at the One Call Stadium.
Paudie O'Connor opened the scoring early before Clucas' moment of brilliance was followed by Dom Jefferies' effort late on.
The Stags have now lost eight of their past nine matches and failed to test keeper Zach Jeacock on a night to forget.
Christy Pym made two good saves in as many minutes as Lincoln started well.
He turned a fierce Tom Bayliss shot away at his near post from Tendayi Darikwa's inviting pass.
From the corner Pym then had to block a point-blank range free header from James Collins.
Mansfield did not heed the warning and from the resulting second corner by Bayliss, O'Connor was allowed a close-range header and made no mistake to put the Imps ahead after nine minutes.
Reeco Hackett thought he had made it 2-0 with a far-post volley but was denied by an offside flag.
In a tight second half, neither keeper was really troubled until near the end.
Ex-Stags midfielder Clucas was booed as he came on as a 72nd-minute substitute.
But in reply he sealed the points with a magnificent corner after 83 minutes that curled in directly under the far angle.
A minute from time fellow replacement Jefferies drilled in a third after the hosts failed to clear a Conor McGrandles cross to seal a first win in five outings.
Report supplied by PA Media.
