Timmy Abraham was controversially sent off on his debut as Maidstone were knocked out of the FA Trophy.
Striker Abraham - a loan signing from Boreham Wood - saw red for catching Reece Hall-Johnson in the face with his boot with United 3-0 down at National League high-fliers Barnet.
It was a case of Abraham attacking a cross and Hall-Johnson going in low with his head to clear it – but the forward was dismissed.
It made no difference to the outcome, with the Bees worthy winners of the third-round tie, but it was frustrating for the visitors to lose their new signing.
George Fowler’s own goal and a Nicke Kabamba double put the Bees in charge at half-time.
Dale Gorman scored direct from a corner as the hosts added their fourth in the final 20 minutes.
Abraham showed early promise with a nice run and cross which just evaded Matt Rush coming in at the back stick.
But that was the Stones’ only real opening of the first half as Barnet took charge at the Hive.
The Bees dominated possession and moved the ball well, with United forced deeper and deeper.
They had to wait until the 31st minute to break the deadlock, however, and that came from an own goal with Idris Kanu’s dangerous cross diverted in by the head of Fowler.
Barnet took the tie away from the National South side with two goals in four minutes before half-time.
Kabamba followed in for number two in the 41st minute after Lucas Covolan parried.
And he scored again after rounding Covolan, who’d come out his area, and rolling the ball into an empty net.
Maidstone introduced Barnet old boy Michael Petrasso for Razzaq Coleman De-Graft at half-time - the Canadian playmaker receiving warm applause from the home crowd.
A nice Petrasso pass released Liam Sole, who had the Stones’ first shot on target shortly after the restart.
But Maidstone found themselves a man down on 53 minutes with Abraham sent off for catching Hall-Johnson in the head following a cross into the Barnet box.
It appeared to be no more than an unfortunate coming-together with Hall-Johnson’s head low rather than Abraham’s foot high.
The ball was there to be won and both players went for it - as their respective managers would expect.
A fourth goal for Barnet followed in the 73rd minute with captain Gorman’s corner from the left going straight in.
Barnet: Walker, Hall-Johnson (Cropper 57mins), Collinge (Stevens 46mins), Gorman, Kabamba (Hooper 70mins), Kanu, Pritchard, Hartigan, Hartigan, Oluwo, Potter, Brunt. Subs not used: Gillmore, Coker, Armstrong, Okimo.
Maidstone: Covolan, Hoyte, Fowler, Greenidge, Sole (Brown 71mins), Corne, Gurung, Kyprianou, Coleman De-Graft (Petrasso 46mins), Rush (Wanjau-Smith 72mins), Abraham. Subs not used: Earle, Ezennolim, Reynolds, Court.
Referee: Aji Ajibola.
Attendance: 636 (126 away).