A mistake from keeper Joe Fryer gifted Kane Hemmings a goal that proved enough to see off visitors Stevenage and extend Mansfield's unbeaten run to eight games.
Hemmings struck on 24 minutes as Joel Byrom lofted a long free kick into the box which the young keeper failed to grab and the ball ran loose behind him for an easy tap-in.
Mansfield continued to create chances but failed to find a second goal and in added time at the end of the half were relieved to see Chris Whelpdale send a low shot wide of the far post through a crowd of players.
Stags thought they were 2-0 up in the 57th minute when Hemmings again punished Fryer for failing to hold the ball with a close range finish.
The goal seemed to have been given then suddenly was chalked off and a free -kick given to Stevenage.
Stevenage failed to register a shot on target in the entire 90 minutes as home keeper Conrad Logan chalked up an easy second successive clean sheet.