After Warner had whacked 110 not out off 65 balls at the SCG on Friday, setting the Sixers a target of 190 to win, Smith stepped up and upstaged his long-time international teammate.
The Test batsman crunched 100 in an electric knock which included five fours and nine sixes.
Smith briefly threatened to race to the fastest BBL ton (39 balls) but still left the SCG with a record to his name.
After overruling Babar Azam to take the strike in the power surge, the former Australian captain punished Ryan Hadley with four back-to-back sixes in an over.
In total, the Sixers batsman humiliated the Thunder bowler by dispatching him for a record 32 runs off a single over.
"We knew we had to go hard from the outset because Davey played a beautiful knock," Smith told Kayo Sports.
"I got off to a really good start with Babar, I thought he played really nicely, we got a partnership together and that set the foundation, and we went on from there.
"It definitely felt shorter towards the members' (stand) and I was fielding down towards long-on and it didn't feel like a huge hit.
"I thought when I go to bat that I'd target that as much as possible and I hit quite a few bombs over that side."
And not only did Smith give Hadley a hard night but he also stole Warner's limelight and hope of pulling off an upset for the Thunder.
Battling a knee complaint that ruled him out of Monday's loss to the Melbourne Renegades, the 39-year-old Warner raced to a fourth-straight 50 and left the Sixers' bowlers second guessing themselves as he brought up his ton.
Warner's knock takes him atop of the BBL runscoring charts and the veteran batsman even made light work of Mitchell Starc - playing his first game in the competition in 11 years - by sending the Test bowler for a six over backward point.
But any sense that would be enough to secure a win - and put a dent in the Sixers' finals hopes - were put to bed by an 141-run opening stand between Azam (47 off 39) and Smith.
On a rapid outfield, Smith was in fine touch from the get-go before falling for 100 when he was stumped by Sam Billings as he came down the wicket to Tanveer Sangha.
The fall of Smith briefly opened the door for the Thunder after Moises Henriques, Sam Curran and Josh Philippe had all departed for single figure scores.
But Jack Edwards (17 not out) thrashed Hadley for a six to give the Sixers a win with 16 balls to spare.
The Sixers moved up to fourth with the win and can lock in a finals berth by beating the Brisbane Heat on Sunday.
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