A spectacular knock by Laurie Evans propelled the Perth Scorchers to claim a record fourth Big Bash League title on Friday, defeating Sydney Sixers by 79 runs in the final at Melbourne's Docklands Stadium.

Thanks to an unbeaten 76 by Evans, the Scorchers amassed 171-6 before comfortably defending the total with veteran seamer Andrew Tye taking three wickets to ensure the target was never threatened.

"We're just so appreciative that everyone was able to come together and we were able to make this tournament happen, and we were able to get to the end of it," Scorchers captain Ashton Turner said during the presentation ceremony.

The Scorchers were reduced to 25-4 after being sent in to bat, with spinner Nathan Lyon (2-24) taking the prized wickets of Mitchell Marsh and Colin Munro, who both departed in single digits.

A 104-run partnership between Evans, whose 41-ball knock included four sixes, and Turner (54) restored order to the innings.

In reply, the Sixers lost wickets at regular intervals as pacers Tye (3-15) and Jhye Richardson (2-20) inflicted maximum damage and caused the required run-rate to steadily climb.

Batsman Daniel Hughes, returning from an ankle injury but still visibly restricted, top-scored with 42 before being run-out by Marsh, triggering a collapse which resulted in the side being bowled out for 92.

The loss ends a horror week for the Sydney side, during which batsman Steve Smith's request to play as a COVID-19 replacement was rejected by league organisers after the squad was decimated by injury and illness.

"It's been a pretty extraordinary season with what's gone on," Sixers captain Moises Henriques said.

"Perth was too good for us tonight, and they were too good for us a few times this year."

Due to state border restrictions denying the Scorchers a home final in Western Australia, the decider was played before a modest Victorian crowd.

The length of Australia's premier Twenty20 tournament has come into question this season on the back of disappointing attendances and television ratings, with a slew of current and former players calling for the competition to be shortened. 

(Reporting by Joel Dubber in Perth, editing by Pritha Sarkar) ((Joel.Dubber@thomsonreuters.com;))