Stevenage crashed to their second home defeat in just three days as Barnet came to Broadhall Way and claimed all three points with an impressive performance.
After a stuttering start Stevenage have taken just five points from a possible 15 and manager Wayne Turner is facing increasing pressure from a disillusioned home support.
However, Stevenage began this vital contest brightly, and after a well-worked move in the 12th minute the lively Graeme Tomlinson might have done better as he blasted over from close range following a knockdown from Kirk Jackson.
Although both sides shared equal possession it was Barnet who created the better of the chances with Ben Strevens seeing a shot come back off the bar after seven minutes following Robin Trott's poor clearance from a corner.
Mark Gower forced a diving save from Stevenage keeper Mark Westhead after the home defence was again undone.
As the first half wore on the chances lessened and Stevenage saw their best effort come in injury-time when Tomlinson reacted instinctively to a poor clearance from keeper Lee Harrison only to see his effort glance just wide of the post.
Barnet began more aggressively at the start of the second half and again hit the woodwork in the 48th minute when Gower saw a long-range free-kick come back off the bar and Jason Soloman then headed the rebound over.
With both sides unable to convert their chances it was fitting that Barnet took the lead from the penalty spot. Junior Agogo found the back of the net as he fired his penalty to Westhead's right-hand post after Matt Fisher was adjudged to have handled Agogo's cross.
Barnet looked to have made the game safe with a second goal in the 77th minute which would have graced any Champions League match as Strevens fired home a spectacular overhead kick from just inside the area following a Matt Gledhill cross.
Stevenage pulled a goal back with nine minutes left and again it was from the spot as Jason Goodliffe blasted his spot-kick home after Strevens had handled a Tomlinson drive in the area.
The goal failed to spark a late revival however and indeed it was Barnet substitute Wayne Purser who made the biggest impact as he twice shot wide in the closing minutes as the visitors threatened to embarrass their hosts further