Caretaker manager Adam Murray made it two wins in four days as the Stags made it through the potential banana skin FA Cup first round replay at Conference.
A 61st minute goal by Ollie Palmer goal, who might have had a hat-trick but for two fine stops by Arsenal loan keeper Josh Vickers, earned a second round tie at Cambridge.
However, in the first half it needed a goalline clearance by the recalled Liam Marsden to stop the non-leaguers grabbing the lead.