The recent signing from Stoke found the roof of the net from a narrow angle after Lee Brown's shot had been deflected into his path.
Fabian Broghammer had fired the home side in front from Brown's left-wing cross after 77 minutes but substitute Harry Crawford levelled for the visitors with a low shot in the last minute.
Crawford picked his spot from 10 yards just moments after being guilty of a glaring miss when he shot over an unguarded net.
But an 8,000 Friday night crowd roared Rovers to their fourth win in six games under Ward and a result which lifted them out of the bottom two.
Rovers made a fast start with Broghammer having a shot deflected just off target and Brunt and Mark McCrystal also going close.
But Barnet, driven on by player-boss Edgar Davids, gradually got into the game and the Dutchman turned the clock back with one moment of magic after 59 minutes, forcing a fine save from Steve Mildenhall with a perfectly-struck shot from 35 yards.