Kansas City will be aiming to become just the ninth team and the first in 19 seasons to win back-to-back Super Bowls when they take on San Francisco in the NFL's decider in Las Vegas on Sunday.

The same two teams met in the Super Bowl four years ago, with Chiefs coach Andy Reid again opposing 49ers coach Kyle Shanahan.

"The 49ers have a lot of talent. They're a better team than the one we played (in 2020)," Reid said. The Chiefs won that game 31-20.

Only four head coaches have at least three Super Bowl wins, and each of the previous three instances of a coaching rematch in the Super Bowl has gone to the victor of the first match-up.

That would be a positive omen for Reid.

The 65-year-old is closing in on all-time legends on the career wins list and is 2-2 in Super Bowls, including a victory over the 49ers in Super Bowl LIV.

He gives an immense amount of credit to two-time NFL MVP Patrick Mahomes and a reconstructed defence. In three career games against the 49ers, in the regular season and post-season, Mahomes is 3-0 with 1,023 yards, eight touchdowns and three interceptions.

"I think the quarterback is as hard to beat as anyone who's ever played the game," Shanahan said.

"The things he can do from a talent standpoint, and then you pair that up with his scheme with Andy, how Andy runs a team with Mahomes's experience now."

Mahomes, 14-3 in 17 career playoff games, and is the youngest quarterback to start four Super Bowls in league history at age 28.

Winning on Sunday would give him three Super Bowl wins -- something five other quarterbacks have accomplished -- and keep him ahead of Tom Brady's record pace of seven wins in 10 appearances. Brady was 30 when he started his fourth Super Bowl.

"I mean, I'm not even close to halfway," said Mahomes, who took his only Super Bowl loss and one of his two AFC Championship Game defeats head-to-head against Brady.

"So right now, it's doing whatever I can to beat a great 49ers team and trying to get that third ring.

"Seven seems like a long way away."

The 49ers won't see many familiar faces on the defense of the Chiefs, which has retained only defensive tackle Chris Jones and replaced 10 other starters from Super Bowl LIV. But these aren't the yesteryear 49ers, either.

San Francisco's remodelling includes changes at quarterback and running back. Christian McCaffrey, acquired via trade from the Carolina Panthers, tied for the NFL lead with 21 touchdowns in the regular season to become an MVP finalist alongside quarterback Brock Purdy.

Purdy stormed to stardom with a 21-5 combined record in the regular season and playoffs the past two seasons.

He underwent elbow surgery after last year's NFC Championship Game, and now has the 49ers in their eighth Super Bowl, tied for second-most.

San Francisco is shooting for a sixth Lombardi Trophy, which would match the Pittsburgh Steelers and New England Patriots for the record.