Quarterback Joe Burrow led the Cincinnati Bengals into their first Super Bowl since 1989 with a stunning upset of the Kansas City Chiefs on Sunday as the Los Angeles Rams outmuscled the San Francisco 49ers to advance to the NFL showpiece.

After the nerve-shredding drama of the divisional round, Sunday's conference championship games delivered more nail biting action as the battle for Super Bowl berths reached its climax.

In Kansas City, Burrow and the Bengals overturned a 21-3 first half deficit against the rampant Chiefs offense led by Patrick Mahomes to snatch a 27-24 win in overtime.

Rookie Evan McPherson kicked the winning points for the Bengals after Burrow had hauled his team back into contention with a performance that included two touchdowns and 250 yards with 23 of 38 passes completed.

"Big win for us," said Burrow. "This is something I always wanted, to play in a Super Bowl and I couldn't be with a better group of guys."

"We're not done yet," added Bengals coach Zac Taylor. "We've got a special team. Everyone stepped up, man. We knew it would come down to one team making the plays to win, and our guys did that."

Victory was sweet for Burrow, whose rookie season last year was cut short by a horrific knee injury.

Los Angeles Rams kicker Matt Gay puts his team ahead against the San Francisco 49ers
Los Angeles Rams kicker Matt Gay puts his team ahead against the San Francisco 49ers GETTY IMAGES NORTH AMERICA via AFP / RONALD MARTINEZ

It was a stunning AFC Championship defeat for the host Chiefs, who were seeking a third consecutive Super Bowl trip after winning in 2020 and losing to Tampa Bay last year.

Cincinnati will try to win the Super Bowl for the first time since the club began play in 1968, having lost to San Francisco in 1982 and 1989 in its only prior appearances in the NFL spectacle.

Chiefs star Mahomes threw for 275 yards and three touchdowns but surrendered his first two interceptions in four AFC finals.

Mahomes could only look on in disbelief as the Bengals celebrated.

"When you're up 21-3 in a game, you can't lose it, and I put that on myself," Mahomes told reporters later.

Cincinnati kicker Evan McPherson celebrates after his game-winning field goal to upset the Kansas City Chiefs
Cincinnati kicker Evan McPherson celebrates after his game-winning field goal to upset the Kansas City Chiefs GETTY IMAGES NORTH AMERICA via AFP / JAMIE SQUIRE

As well as Burrow, the Bengals had the trusty boot of rookier kicker McPherson to thank for the win. McPherson had booted the Bengals into the AFC title game with a 52-yard effort to seal a 19-16 upset of Tennessee last week.

McPherson said the Bengals had stayed calm despite trailing by 18 points early in Sunday's game.

"Nobody blinked an eye," McPherson said. "I think we all thought we were definitely going to come back and find a way to win. That's what we've done all throughout the whole year."

In Los Angeles, the Rams ensured they will play a Super Bowl on home turf after staging a comeback of their own to beat the 49ers and end a six-game losing streak against their Californian rivals.

The 49ers edged the Rams 27-24 on the final game of the regular season earlier this month to squeeze into the playoffs.

History looked to be repeating itself on Sunday as the 49ers took a 17-7 third quarter lead thanks to touchdowns from Deebo Samuel and George Kittle either side of a Robbie Gould field goal.

But with the game on the line, Rams quarterback Matthew Stafford led scoring drives which yielded a Cooper Kupp touchdown and two Matt Gay field goals to give Los Angeles a 20-17 lead.

San Francisco quarterback Jimmy Garoppolo had one last chance to find a game-winning score, but gave up an interception to Travin Howard in an attempt to avoid a sack which effectively ender the game.

"That was an unbelievable performance by our team," Stafford said afterwards.

"It didn't start the way we wanted it to, guys battled. I said in the locker room there's no way we're not going to win this damn game. Our guys put our minds to it and came out here and did it."

It is the second time in three years the Rams have reached the Super Bowl after advancing to the 2019 edition, where they were beaten by Tom Brady's New England Patriots.

Stafford, who joined Los Angeles last year in a blockbuster trade from the Detroit Lions, will be playing in his first Super Bowl at the age of 33.

"I'm at a loss for words," he said. "I'm just having a blast playing ball with these guys and, shoot, we've got one more it's our home stadium -- let's get it done."

Stafford's dream night almost turned to disaster late in the game but what should have been a straightforward interception was fumbled by 49ers safety Jaquiski Tartt.

"I deserve all the criticism my way," Tartt wrote on Twitter later Sunday. "Let my brothers down!! It still won't define me as a person/player."