Match ends, Barnet 1, Plymouth Argyle 0.
Barnet captain Andy Yiadom scored his first goal since September to beat Plymouth, who slipped to third place.
There were 14 minutes added on at the end of the first half after Pilgrims defender Jordon Forster was taken off on a stretcher with a head injury.
Argyle came closest before the break, Reuben Reid firing wide and James Pearson heading an effort off the line.
Yiadom netted on the turn after a forceful John Akinde run, making it just one loss in eight for the Bees.
Barnet remain 15th in League Two while the Pilgrims host Oxford, who leapfrogged them into second, on Saturday.
Speaking after the match, Plymouth boss Derek Adams revealed first indications say Forster has a broken jaw while striker Ryan Brunt, who was also forced off, has a suspected cruciate ligament injury.
Barnet manager Martin Allen told BBC Radio London:
"I think they played quite well in the first half and we didn't actually make our mark on the game.
"At half-time I encouraged our players to show some more self-belief, a bit more tenacity and some more courage.
"It was a very, very good second-half performance - I'd say up there with the best."
- 34RandallSubstituted forRobertsat 62'minutes
- 12GambinSubstituted forNelsonat 86'minutes
- 22StevensSubstituted forMuggletonat 55'minutes
- 28ForsterSubstituted forMellorat 18'minutes
- 14JervisSubstituted forNardielloat 78'minutes
- 17BruntSubstituted forTannerat 34'minutes
- Gavin Ward
- Shots on Target
Second Half ends, Barnet 1, Plymouth Argyle 0.
Attempt missed. Reuben Reid (Plymouth Argyle) header from the centre of the box is close, but misses to the left.
Foul by Andy Yiadom (Barnet).
Kelvin Mellor (Plymouth Argyle) wins a free kick on the left wing.
John Akinde (Barnet) wins a free kick in the attacking half.
Foul by Peter Hartley (Plymouth Argyle).
Attempt saved. John Akinde (Barnet) right footed shot from outside the box is saved in the top centre of the goal.
Attempt saved. James Roberts (Barnet) right footed shot from long range on the right is saved in the top left corner.
Attempt saved. Peter Hartley (Plymouth Argyle) left footed shot from outside the box is saved in the centre of the goal.
Substitution, Barnet. Michael Nelson replaces Luke Gambin.
Attempt blocked. Kelvin Mellor (Plymouth Argyle) right footed shot from the left side of the box is blocked.
Foul by James Pearson (Barnet).
Graham Carey (Plymouth Argyle) wins a free kick in the attacking half.
Alie Sesay (Barnet) wins a free kick in the defensive half.
Foul by Reuben Reid (Plymouth Argyle).
Substitution, Plymouth Argyle. Daniel Nardiello replaces Jake Jervis.
Attempt saved. Sam Muggleton (Barnet) right footed shot from outside the box is saved in the centre of the goal.
Attempt missed. Craig Tanner (Plymouth Argyle) right footed shot from outside the box is close, but misses to the left.
Attempt missed. Jake Jervis (Plymouth Argyle) right footed shot from outside the box misses to the left from a direct free kick.