From the outset Stevenage took the game to a Barnet side managed by former Boro boss Paul Fairclough.
Indeed it took just three minutes for the home side to create an opening, and it was Anthony Elding who should have done better when he found himself free on goal could only to drive his effort against Bees keeper Scott Tynan.
Tynan was again forced into the action in the 14th minute when he produced another vital save with a spectacular tip-over following a long-range effort from Dannie Bulman.
Stevenage did have the ball in the back of the Bees net but Dino Maamria's turn and shot on 23 minutes was disallowed for offside.
Liam Hatch was the major danger for the visitors and after seeing a shot deflected wide in the 20th minute, he looked odds on to score just before the break.
However, he was only able to chip the ball past home keeper Andy Woodman and wide of the goal.
The game was to turn in first-half stoppage time when Barnet's Dwane Lee received a straight red card for a use of the elbow.
Stevenage made the most of the added man advantage and after piling on the pressure in the second half they finally went ahead in the 58th minute when Anthony Elding provided the decisive touch following a neat move.
Barnet did hit back just minutes later when Conference hot-shot Giuliano Grazioli forced the ball home following an untidy goalmouth scramble.
But it was Stevenage who were to have the final say and when George Boyd was fouled in the area in the 64th minute it was Maamria who stepped up to blast the penalty home and seal Stevenage's credentials as play-off contenders.