The Kansas City Chiefs beat the top-seeded Baltimore Ravens 17-10 to claim the AFC championship and earn a trip to the Super Bowl for the fourth time in five years.

Patrick Mahomes completed 30 passes for 241 yards, including one touchdown throw to Travis Kelce that had his popstar girlfriend Taylor Swift jumping up and down in jubilation in a private box at Baltimore's M&T Bank Stadium on Monday (AEDT).

The Chiefs now head to Las Vegas for the February 11 Super Bowl, where they will defend their crown against the San Francisco 49ers, who beat the Detroit Lions in the NFC championship game.

No team has won back-to-back NFL titles since Tom Brady led the New England Patriots to the Vince Lombardi Trophy in 2004 and 2005.

"It's been a heck of a year, we're not done yet," Mahomes said.

"We've been underdogs the last few games but we never feel like underdogs - we've got a lot of guys on this team that know how to win.

"When the playoffs came around we were going to make it happen, and now we're in the Super Bowl the job's not done."

The first Super Bowl held in Las Vegas is already expected to be one of the splashiest ever, but the buzz around America's biggest party is sure to be dialled up a few notches with Swift and her legion of fans known as "Swifties'' on board.

The AFC championship was highlighted by a marquee quarterbacking match-up between Mahomes, the twice and reigning NFL most valuable player, and Lamar Jackson, who claimed the honour in 2019 and is favoured to add another for his work this season.

The Chiefs, playing in their sixth straight championship game, were quick out of the blocks, Mahomes hitting Kelce with a 19-yard touchdown strike to cap an 81-yard opening drive.

The Ravens answered right back, needing just six plays to find the end zone, Jackson pulling off a Houdini-like escape avoiding a sack, then finding Zay Flowers for a 30-yard touchdown.

The furious early pace continued with Mahomes engineering a clinical nine-minute drive on Kansas City's next possession that spanned parts of both the first and second quarters and finished off with Isiah Pacheco powering over from the two.

Helped by two personal foul penalties by Baltimore, the Chiefs added to their lead just before the half on a Harrison Butker 52-yard field goal, sending the visitors to the break leading 17-7.

The Ravens and Chiefs finished the regular season with the two top-ranked defences, and scores were hard to come by in the second half.

Baltimore's sputtering attack looked ready to come back to life late in the third quarter when Jackson hit Flowers with a 54-yard pass play to get into scoring position.

Jackson would look Flowers' way again, but just inches from the goal line the receiver would fumble, turning the ball over to Kansas City.

Baltimore would add some suspense with a Justin Tucker 43-yard field goal trimming the Chiefs' lead to 17-10 with 2:34 to play, but they could not complete a storybook comeback.

In Santa Clara, California, Brock Purdy threw for 267 yards and a touchdown as the San Francisco 49ers rallied from 17 points down at half-time to beat the Detroit Lions 34-31 and reach the Super Bowl.

The 49ers (14-5) scored 17 points in an eight-minute span of the third quarter to tie the NFC championship game, then pulled away in the fourth quarter to earn a rematch against Kansas City after losing to the Chiefs in the Super Bowl four years ago.

San Francisco mounted the fourth comeback ever from 17 points down or more in a conference title game thanks to some big plays by Purdy and bad mistakes from the Lions (14-6), including two failed fourth downs in field-goal range.

Detroit fell short of reaching the first Super Bowl in franchise history.