LAS VEGAS — Patrick Mahomes, Travis Kelce and the Kansas City Chiefs are back-to-back Super Bowl champions.

Mahomes threw a 3-yard touchdown pass to Mecole Hardman with 3 seconds left in overtime, and the Chiefs rallied to beat the San Francisco 49ers 25-22 on Sunday, becoming the first repeat Super Bowl champs in 19 years and ninth overall.

With pop star Taylor Swift watching boyfriend Kelce from a suite, the Chiefs captured their third title in five years and firmly established themselves as a dynasty.

The NFL’s first Super Bowl in Las Vegas was a sloppy, mistake-filled affair that was mostly boring until the back-and-forth fourth quarter and OT. It was the second of 58 Super Bowls to be tied after regulation, and the first played under new overtime rules under which both teams got the ball.

The Chiefs trailed 22-19 after Jake Moody kicked a 27-yard field goal on the first possession of overtime, but Mahomes rallied the Chiefs, completing another impressive comeback in a rematch of a Super Bowl four years ago.

Mahomes ran 8 yards on fourth-and-1 to keep the Chiefs' chances alive and then scrambled 19 yards to set up the winning score.

After he connected with a wide-open Hardman, the Chiefs ran on the field as red-and-yellow confetti fell on the turf.

The most excitement in the first half came when a frustrated Kelce bumped Andy Reid on the sideline, knocking the Chiefs' 65-year-old coach a few steps back after teammate Isiah Pacheco fumbled inside the red zone during the second quarter.

The action picked up after a crucial blunder by San Francisco’s special teams set up Mahomes’ 16-yard TD pass to Marquez Valdes-Scantling for a 13-10 lead.

Brock Purdy and the 49ers answered but they couldn’t make enough plays, denying Mr. Irrelevant an opportunity to go from last pick in the 2022 NFL draft to Super Bowl champion.

Mahomes and Reid are now halfway to Tom Brady and Bill Belichick, who won six championships in 20 years together with the New England Patriots and were the most recent team to go back-to-back following the 2003-04 seasons.

The 28-year-old Mahomes becomes the fourth starting QB to win three Super Bowls — joining Brady, Joe Montana, Terry Bradshaw and Troy Aikman — and second-youngest.