The Sixers, bidding for a third straight crown, will meet rivals Perth Scorchers in Friday night's title-deciding match at Marvel Stadium.

And the men in magenta are certain to ask the question about Steve Smith yet again after Steve O'Keefe (calf) and Jordan Silk (hamstring) both suffered injuries in the field at the SCG.

Sixers captain Moises Henriques, who scored 13 in a remarkable chase of 168 that Kerr finished in scarcely-believable fashion, also tweaked his calf on an eventful night.

Jonathan Wells' unbeaten 62 rallied Adelaide from 3-21 to 4-167 in the Challenger final.

Kerr underlined the hosts' depth in response, carrying his bat as they reached 6-170.

"That was wild. It hasn't really sunk in," Kerr said.

"I was feeling pretty calm.

"Looking forward to that final, we are missing a few guys but it shows that we can get the job done."

Kerr benefited from two chances, having been dropped in the deep by Matthew Renshaw on 16 after Test keeper Alex Carey missed a stumping off the first ball of the innings.

Harry Conway, who was the final-over hero of the Strikers' thrilling victory over Sydney Thunder on Sunday night, was asked to defend 12 runs in Wednesday night's final over.

Conway started with the wicket of a well-set Sean Abbott for 41 but ended with Kerr's 12th boundary.

There was no shortage of drama between.

A hobbled Silk walked to the middle, scored a single, watched Kerr wallop a six then retired hurt because the Sixers wanted a fully-fit body at the non-striker's end for the final ball.

The move appeared to not go down well with Adelaide captain Peter Siddle, while Adam Gilchrist opined on Fox Sports that "it's probably not in the spirit of the game".

Kerr has enjoyed a coming-of-age summer, earning selection in the league's team of the tournament voted on by coaches, but not even he could have foretold a stunning series of events.

The 25-year-old was promoted to open for the Sixers after their fresh bid for former skipper Smith to play was rejected despite Josh Philippe being an enforced omission because of COVID-19.

Daniel Hughes, another candidate to open if not for his ankle injury, failed a pre-match fitness test.

Kerr, having previously tallied 77 runs at 11 from 11 BBL innings, produced a masterful dig full of sensible strokes and powerful blows.

"It is disappointing," Siddle said.

"A few missed opportunities with bat and ball."

Veteran spinner O'Keefe tweaked his right calf after logging tidy figures of 1-21 from four overs, meaning this knock-out match could be his swansong.

Silk is also in extreme doubt for the high-stakes match in Melbourne, which will mark the fifth time that Perth and the Sixers have squared off in the final game of the season.

The Sixers' struggle to field a fit XI could prompt Cricket Australia (CA) to rethink its decision to block Smith from making a cameo in the finals.

Australian Associated Press