On the final day of the first week of the 2026 NCAA Tournament, the reigning national champion saw its dream of a repeat come to an end.

In arguably the biggest upset of the opening week of the tournament, No. 9 seed Iowa knocked off No. 1 seed Florida 73-72 thanks to a 3-pointer from Alvaro Folgueiras with 4.5 seconds remaining.

The Hawkeyes had led by as many as 12, but saw the Gators claw back to take a two-point lead with eight seconds remaining after Isaiah Brown split two free throws.

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Iowa guard Bennett Stirtz took the inbound pass and had a two-on-two in front of him, after Florida had opted to press and Stirtz’s primary defender, Boogie Fland, gambled to try to get a steal. As Stirtz took the ball up the court near the 3-point arc, Gators forward Thomas Haugh bit to cut off Stirtz’s path to the basket, leaving Folgueiras wide open in the corner to knock down the go-ahead 3 with four seconds remaining.

ARE. YOU. JOKING.

IOWA LEADS. THIS IS MARCH. #MarchMadnesspic.twitter.com/sNDHTqaGj1

— NCAA March Madness (@MarchMadnessMBB) March 23, 2026

Florida had a chance to pull out a win, but was unable to even get a shot off, with Xaivian Lee driving to the basket and trying to dump it off to Haugh, only for an Iowa defender to stick his hand in to block the pass as time expired.

IT'S ALL OVER! THE CHAMPS GO DOWN 🤯

IOWA IS HEADED TO THE SWEET 16! 😱 #MarchMadnesspic.twitter.com/I7DldUMrjD

— NCAA March Madness (@MarchMadnessMBB) March 23, 2026

With the win, Iowa earned a trip to its first Sweet 16 since 1999, a milestone it reached in just its first season under coach Ben McCollum.

The Gators became the first No. 1 seed to lose in the tournament this season.

Folgueiras' triple was one of two game-winning shots Sunday, with St. John's guard Dylan Darling giving his team a 67-65 victory over Kansas earlier in the day on a layup as time expired.

This article originally appeared on USA TODAY: Iowa basketball upsets Florida in March Madness with 3 heard 'round the world