San Francisco 49ers' head coach Kyle Shanahan speaks with his players during their Super Bowl loss to the Kansas City Chiefs

Las Vegas (AFP) - San Francisco coach Kyle Shanahan absorbed a third agonizing Super Bowl defeat Sunday, but vowed the 49ers would bounce back after being denied in overtime by the Kansas City Chiefs in the NFL championship showpiece.

“We all hurt,” Shanahan said after the 49ers fell 25-22 to the Chiefs – who won it with a Patrick Mahomes touchdown pass with three seconds left in overtime.

“Everyone knows how it feels. Don’t have a lot of words for it. Obviously we’re hurting. Our team’s hurting. That’s how it goes when you put yourself out there.

“Real proud of our guys,” he added. “No regrets with our team, the guys played so hard today, not everything was perfect by no means. But if we’re going to lose with a group of guys, I’ll take those guys any time.

“We’ll take some time and get over this and come back next year ready to go.”

The 44-year-old coach, regarded as one of the most innovative minds in the NFL – has now seen three Super Bowl chances slip away.

He was the offensive coordinator when the Atlanta Falcons blew a 28-3 lead to be reeled in by Tom Brady and the New England Patriots, the biggest collapse in Super Bowl history.

Three years later, Shanahan came up short once more when his 49ers team squandered a double-digit advantage and conceded 21 unanswered fourth-quarter points in a 31-20 loss to Patrick Mahomes and Kansas City.

While the 49ers have won five Super Bowl titles, Sunday’s defeat extended their current drought to 29 seasons.

Quarterback Brock Purdy threw for 255 yards and Jauan Jennings threw for a touchdown and caught a touchdown for San Francisco.

But the 49ers saw a punt reception go awry, Jake Moody missed an extra point attempt and linebacker Dre Greenlaw exited before halftime with an Achilles injury suffered when he slipped jogging onto the field.

San Francisco led 10-0 in the second quarter and were up 19-16 when the Chiefs produced a field goal to tie it with three seconds left in regulation.

The 49ers settled for a field goal on the opening possession of overtime, which gave the Chiefs had a chance to win it with a touchdown.

Shanahan admitted there was little comfort he could offer his players.

“I don’t care how you lose when you lose Super Bowls, especially ones you think you can pull off. It hurts,” he said.

“But I think when you’re in the NFL I think every team should hurt except for one at the end.

“We’ve gotten pretty damn close, but we haven’t pulled it off and we’re hurting right now, but (that) doesn’t take away from how proud of our guys I am.”