A closely fought first half ended on a sour note. Carlisle's Grant Smith cynically scythed down Thomas Butler to pick up the night's first yellow card, followed seconds later by Swansea's Andy Robinson for his over the top remonstrations.
Tempers were still raw as half-time saw police called to a scuffle in the tunnel as the players left the field.
Robinson's frustration could be understood. He put the ball in the net only for it to be disallowed and he hit the woodwork three times as he orchestrated Swansea's attacks to good effect.
At times the visitors penned Carlisle back in their own half for long second-half spells, but it was the Cumbrians who had had the better of the opening exchanges.
United broke quickly in the fifth minute, but Marc Bridge-Wilkinson's shot was comfortable for Dorus de Vries. Then in the ninth minute Smith saw his effort whistle just wide of the post as United started to gain the advantage.
Under pressure, Dennis Lawrence gave away a corner and de Vries did well to punch Simon Hackney's ball round the post.
Danny Livesey came to Carlisle's rescue when Jason Scotland raced upfield to set up Febian Brandy for a shot that the United skipper blocked.
De Vries then pulled off a great save after Scott Dobie turned Kevin Austin to fire in from a tight angle from an Evan Horwood pass.
But Swansea fought back with Robinson hitting the crossbar for the first time with a 34th minute free kick. Then 29-goal top scorer Scotland fired a screamer just over the bar before Danny Graham came close for Carlisle just before the break.
A 49th minute Robinson free-kick had Keiren Westwood palming it onto the underside of his crossbar and needing David Raven to make a goal-line clearance.
Robinson struck the crossbar for a third time with a ball across the face of goal that almost crept in at the far post and Livesey twice saved Carlisle, blocking Scotland's shot and heading clear a Guillem Bauza close-range effort.
For United Dobie flicked a header from a good Raven cross too close to the keeper and de Vries made a super one-handed diving save to turn away a Hackney effort.
Both sides kept battling until the end and four more players - two from each side Bauza and Scotland for Swansea and Bridge-Wilkinson and Raven for Carlisle - got booked.
A draw was a fair result and both sides still believe they can be champions.