Sam Heazlett showed the value of hanging in as he turned a batting struggle into a match-winning display against the Sydney Thunder in the BBL Knockout final.

Heazlett was 19 off 26 balls in the Brisbane Heat's chase of 159 before he finally scored a boundary and that flicked a switch for the left-hander, who scored 51 off his next 23 deliveries in a career-best T20 score of 74 not out.

With Heazlett labouring and Marnus Labuschagne controversially run-out, the asking rate had pushed above 11-an-over but, having been brought into the side as a match-up for the Thunder legspinner Tanveer Sangha, he then took to him with a pair of leg-side sixes as the game swung back to the Heat.

"My head was probably spinning a bit early," Heazlett said. "I played and missed at a few balls but we had more batting to come, Jimmy's [Peirson] been in great form this season and we had full confidence that we could lift the rate towards the end.

"I was looking to go hard towards the short boundary with the legspinner on, lucky enough to get a few away and that took the pressure off a little bit and from there tried to hit the ball hard and thankfully it came off."

When Heazlett was recalled for the Eliminator final to break up a batting order filled with right-handers, he had not played since January 2 in a season that had brought 99 runs in six innings - 48 of those in one knock against the Hobart Hurricanes where he struck five sixes - and he admitted to uncertainty at the start of his innings.

"I haven't scored a whole heap of runs this year. [You] still try to go out there with confidence but you don't want to get out, [it was] two for not many, and I probably wasn't quite as clear as I needed to be, not watching the ball as hard as I should have," he said. "But you have to back your skills. It's good to get that one in now and go into the next game with a few runs under the belt."

Heazlett has had a curious career so far, selected for Australia's limited-overs squad before he had made a one-day appearance for Queensland, debuting against New Zealand in the match where Marcus Stoinis made 146 not out and having statistics in the 50-over game (average 54.05) that far outweigh his T20 numbers (average 18.18).

"[It's been] frustrating…to have pretty good stats in one-day cricket and coming to T20 cricket and know I have what it takes but not being able to do it enough is disappointing," he said. "But thankfully the [Heat] coach and captain had a lot of faith in me. I've enjoyed that middle-order role a couple of times this year, good to have the field out, get my eye in then take it from there."

The Heat, who qualified for the finals series in fourth meaning they would need to win four games in a row to take the title, will now face the Perth Scorchers in the Challenger final on Thursday to decide who plays the Sydney Sixers at the SCG on February 6. The match will be played in Canberra after Perth was put into a five-day lockdown because of Covid-19.