Brisbane Heat will compete in the final of the Big Bash T20 League after clinching a surprise victory over the Melbourne Renegades, who topped the ladder after the group phase.

The pressure was on Luke Pomersbach to get his side, who headed into the clash as the underdogs, off and running at the crease and he didn't disappoint by storming to 112 runs unbeaten and setting the pace for Heat.

Peter Forrest could only muster three runs before getting dismissed by Darren Pattinson but Joe Burns was able to form a formidable partnership with Pomersbach by racking up 33 runs before Aaron Finch ended his time at the crease.

Daniel Christian and Chris Lynn contributed 11 and 20 runs respectively to give the Renegades a chase of 184.

Opening batsman Finch was joined by Alex Hales to kick off the Renegades' innings and while many were expecting a prolific partnership, Lynn dismissed Finch for 23, while England's Hales walked on 20 runs.

While Ben Rohrer was able to rack up 42 runs for the home side, the likes of William Sheridan and Nathan Rimmington were dismissed cheaply to put the Renegades under pressure.

Despite their attempts at a fightback, the Renegades were unable to surpass Heat's lead after 20 overs and lost the match by 15 runs.