League leaders Barnet brought Carlisle's unbeaten start to the season to an end in an excellent top-of-the-table clash.
The Londoners got off to a flying start when they were awarded a controversial penalty inside the first three minutes after Lee Andrews was judged to have handled.
Skipper Ian Hendon stroked in the penalty and further pressure from Barnet saw them add a second on the half hour.
Dean Sinclair hit a low ball across goal which Nick Bailey dummied, giving Cumbrian captain Kevin Gray no chance as he inadvertently smashed the ball into the net.
Carlisle now had little choice but to attack, and were unlucky when Tom Cowan's back-post header was tipped on to the bar by Scott Tynan.
But a minute before the beak, Chris Lumsdon laid off for Brendan McGill to fire at Tynan and force in the rebound.
Poor finishing cost Carllisle dear and they should have been ahead before Barnet struck their third.
Peter Murphy, Karl Hawley and Chris Billy all had shots saved by Tynan who, when beaten, had Hendon on hand to clear Hawley's shot off the line.
Barnet secured all three points when Dwane Lee was left unmarked to head in Simon Clist's corner with 12 minutes to go.