In one of the best BBL innings, Smith launched an astonishing seven sixes in front of 31,165 fans at the SCG on Saturday afternoon in a 64-ball innings for the ages as the Sixers cantered to 3-220.
Sean Abbott then celebrated his call-up to the Australian Test squad for Sri Lanka with 4-43, moving the Sixers to first on the ladder and with one foot in the finals.
And while Perth provided some fireworks of their own on the way to 7-206, this was a day for Smith.
Steve Smith has hit seven sixes on his way to an unbeaten 121. (Mark Evans/AAP PHOTOS)
The century marked his third in the BBL, drawing him level with Ben McDermott for the most in the tournament's history.
Smith has played 32 matches for his three tons, compared with McDermott's 100 games.
Globally, Smith has been something of a forgotten star in Twenty20 cricket, compared with his status as Australia's best Test batter since Sir Donald Bradman with a return to runs this summer.
The 35-year-old has not played a T20 for Australia since last February, and was overlooked for the World Cup squad last year.
He has also been brushed in the past four IPL auctions, featuring only in the Major League Cricket last year of all overseas franchise leagues.
But in the BBL Smith continues to prove his worth, with this his third century in his past seven games.
And it may have been his best yet, after barely hitting a ball since the end of Australia's Test series win over India on Monday.
The right-hander's last 95 runs came off 40 balls, after the Sixers were particularly patient early and 1-24 after five overs.
Smith regularly targeted the short boundary at the SCG, while also cutting behind point with glee when the Scorchers went too wide outside off to try to counteract him.
Two of his sixes came off switch-hits to the short rope, and another was a crisp flick off his pads from Jhye Richardson that sailed into the Bill O'Reilly Stand.
Steve Smith is something else 😲 — KFC Big Bash League (@BBL) Here's all the highlights from his 121* off 64 balls. #BBL14 pic.twitter.com/MTo82oWAv1January 11, 2025
Still, Smith's shot of the day went to the long boundary, picking up a full and wide ball from AJ Tye and hitting it inside out over backward point for six.
Tye copped the brunt of the damage for the Scorchers, going for 0-62 from his four overs while also being taken to by Ben Dwarshuis (23 not out off seven balls).
Richardson also went for 0-51 from his four overs, as Smith and Moises Henriques took him for 24 from the first over of the power surge during a 113-run partnership.
This was a day when everything Smith touch turned to gold, including being caught in the deep in the last over before replays fielder Nick Hobson had put a foot on the rope.
"It was a good one, particularly after the way I started, I could barely spell bat the first 10 balls I faced," Smith said.
Ashton Turner hit 66 from 32 balls for the Scorchers but it was never enough against the Sixers. (Mark Evans/AAP PHOTOS)
"Something just clicked after that, I felt quite nice.
"I love batting here at the SCG. I know the pockets of the ground I can target. We had the short side I was trying to take advantage of.
"And then use the long side when they bowled out there too."
In reply, the Scorchers' faced an uphill battle from the moment Abbott took back-to-back wickets in the fourth over.
Ashton Turner hit 66 from 32 balls to give the visitors a late hope, but 23 from the final over proved too much as Perth stayed fifth on the ladder.
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