Rovers were handed their first loss in seven games at the hands of Barnet.
Gavin Hoyte's early strike was enough to secure all three points for Martin Allen's men who later had skipper Andy Yiadom sent off.
Darrell Clarke made one enforced change to the side that beat Luton Town last time out as Ellis Harrison came in to replace on loan striker Rory Gaffney who has returned to his parent club Cambridge United with new signing Liam Lawrence taking a place among the substitutes.
Barnet started very brightly and were rewarded for their efforts in the fourth minute as Gavin Hoyte put the Bees ahead. Following a long throw from the Barnet right hand side, the ball was bouncing in the penalty area and the former Arsenal man made no mistake firing the ball past Steve Mildenhall.
Rovers faced heavy pressure from Barnet who had the wind behind them in the first period but managed to stay strong and eventually had chances of their own.
First Lee Brown's cross was headed high and wide by Lee Mansell under heavy pressure from Bondz N'Gala before Ellis Harrison headed a decent opportunity into the arms of Jamie Stephens.
John Akinde was proving troublesome for the Rovers back line with his pace and power but failed to test Mildenhall in the Gas goal. At the other end of the field a set piece routine was worked to Tom Parkes who tried his luck from range but dragged his effort just wide of the goal.
Darrell Clarke changed things around at half time replacing Ollie Clarke with Chris Lines which had an instant impact as within two minutes of the restart Ellis Harrison was put through onto goal and forced a good reaction save from Stephens.
The home side rarely threatened in the second half with their only chance falling to top goal scorer John Akinde. After a powerful run through the middle of the field Luke Gambin picked out the former Rovers man in the penalty area but Steve Mildenhall was off his line quickly to deny the big man before gathering the ball at the second opportunity.
Minutes later Barnet were reduced to 10-men as captain Andy Yiadom was given a straight red card by referee Michael Bull following a late challenge on Stuart Sinclair.
Rovers reacted positively, handing latest signing Liam Lawrence his debut for the club as well as bringing Jermaine Easter into the action as they searched for an equalising goal.
The final ball in the final third was seemingly lacking for Darrell Clarke's side however when they did create opportunities, multiple efforts from Ellis Harrison, Matty Taylor and Jermaine Easter failed to hit the target.
Up next for Rovers is the trip to the Kassam Stadium to take on Oxford United before hosting Plymouth Argyle at the Mem on 23rd January.
Barnet: Stephens, Hoyte, Johnson, Dembele, N’Gala, Yiadom (C), Weston, Togwell, Gambin, Akinde (Batt - 80), McLean (Champion - 65).
Unused Substitutes: McKenzie-Lyle (GK), Taylor, Stevens, Odoffin, Gash.
Rovers: Mildenhall; Leadbitter, J. Clarke (Easter - 64), Lockyer, Parkes, Brown; Mansell (C) (Lawrence - 64), O. Clarke (Lines - 46), Sinclair; Harrison, Taylor.
Unused Substitutes: Preston (GK), McChrystal, Montano, Bodin.