SANTA CLARA, Calif. -- One of the weirdest things happened to Brandon Aiyuk on Sunday during pregame warm-ups. The San Francisco 49ers all-pro receiver happened to look at his feet and noticed that a ladybug was attached to one of his cleats.

He took that as an omen.

"Oh yeah, we in there!" Aiyuk recalled to USA TODAY Sports of what he told himself, amid a loud, festive party scene in the 49ers' locker room after the huge, 34-31 comeback victory against the Detroit Lions propelled them to Super Bowl 58.

Everybody knows that ladybugs bring good luck. Aiyuk will now vouch for that fervently.

Hey, sometimes the vibe comes in mysterious ways.

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Thank you, ladybug. Aiyuk's improbable, 51-yard circus catch in the third quarter -- the football ricocheted off the helmet of Lions cornerback Kindle Vildor and into Aiyuk's outstretched arms as he dove for what was actually a grossly overthrown pass -- was perhaps the most pronounced game-changing play as the 49ers rallied from a 17-point halftime deficit.

Sure, there were other key plays that enabled the effort. Tashaun Gibson forced a Jahmyr Gibbs fumble, recovered by Arik Armstead, that set up a quick Christian McCaffrey touchdown. Brock Purdy channeled his inner Lamar Jackson by twice scrambling for 21 yards that led to touchdowns. The Lions went for it twice on fourth down and came up empty both times.

Yet nothing suggested the 49ers were poised to snatch victory in a dramatic reversal of fortune quite like Aiyuk's catch off a deep post pattern. Every big comeback needs some type of jaw-dropper that maybe confirms the rally is real. For the 49ers, this was it. Momentum shift. Complete.

Purdy's first reaction: "Oh my gosh, he caught that."

Fellow receiver Deebo Samuel, running a high crossing route, clearly saw the miracle as it developed.

"I'm thinking he scored," Samuel said.

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Aiyuk popped to his feet and ran into the end zone, looking for a touchdown. The officials, though, ruled that he was down by contact at the 6-yard line. They also picked up the penalty flag that was thrown, apparently for pass interference.

"I saw a flag," 49ers tight end George Kittle recalled. "All of a sudden, I saw him celebrating in the end zone, fake-dunking. I was like, 'He caught it?' Did he one-hand catch it? What did he do?' "

Kittle looked up and found the answers on the Jumbotron screen. 

"I saw the replay," he said. "Just as he intended it to look -- off the guy's facemask and right into his hands."

Aiyuk finished the drive with a 6-yard touchdown catch, three plays after the highlight-film moment, that cut Detroit's lead to seven points. The 49ers ultimately scored 27 unanswered points, taking control of the game.

After flirting with an upset loss to the Green Bay Packers eight days earlier in an NFC divisional playoff, the 49ers can't afford to continue the pattern of sluggish starts if they plan to topple the Kansas City Chiefs in Super Bowl 58. Breakdowns nearly cost San Francisco against Green Bay, then an assortment of errors (including shabby tackling) pushed them into the deep hole against Detroit.

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Against a championship-tested squad led by Patrick Mahomes, the 49ers can hardly afford to spot the Chiefs a big lead or otherwise commit game-swinging gaffes. Sure, the 49ers, who have typically built leads that force opponents to play catch-up, have in the past two outings refuted the narrative that they can't come from behind. Must be a nice confidence boost to get it done.

"That's back-to-back weeks with wins that we weren't supposed to have, apparently," Aiyuk said. "Just two gutsy wins; two wins that just show you the type of team that we have, the mindset, the will and that heart that everybody had."

Still, ladybugs or not, they might not want to press their luck, even in Las Vegas, in the next game.