Patrick Mahomes pulled off another Super Bowl comeback on Sunday as the Kansas City Chiefs snatched a thrilling 25-22 overtime victory over the San Francisco 49ers to win their third NFL championship in five seasons.

In a perfectly scripted finale before a celebrity-studded Las Vegas crowd, including pop icon Taylor Swift, Mahomes hit Mecole Hardman in the end zone with just three seconds of overtime remaining to seal a dramatic win in what was the longest Super Bowl in history.

The win makes Kansas City the first team to win back-to-back Lombardi Trophies in two decades, cementing the franchise's right to be regarded as the NFL's latest dynasty.

"It means a ton," Mahomes said. "With the adversity we dealt with this year and to come through, the guys never faltered."

For long periods, however, it looked as if Kansas City would be denied by San Francisco's ferocious defence.

Chiefs star Travis Kelce -- the boyfriend of watching singer Swift -- had a nightmare start to the game, at one stage blowing up on the sidelines at Kansas City head coach Andy Reid in an extraordinary outburst.

But with Mahomes pulling the strings, the Chiefs finally battled through a below-par performance to deliver when it mattered once more.

It marked the third time that Mahomes has led Kansas City back from double-digit deficits to win the Super Bowl, sealing his reputation as the heir apparent to the legendary Tom Brady. (AFP)