After 21 weeks and 281 games of the NFL season, we've reached the final hurdle on the road to Super Bowl 57.

The usual suspects are here, with the Kansas City Chiefs, the Cincinnati Bengals, the Philadelphia Eagles and the San Francisco 49ers having all reached a Super Bowl in the past five years.

The man expected to be named this season's Most Valuable Player has made it too, with quarterback Patrick Mahomes having led the Chiefs to the AFC Championship Game for a fifth straight year.

However, there have been concerns over how fit the 2018 MVP will be for Sunday's rematch with the Bengals.

And can 49ers quarterback Brock Purdy complete a remarkable journey from being 'Mr Irrelevant' to a Super Bowl starter?

The Chiefs had an injury scare during last week's divisional round as Mahomes was forced off against the Jacksonville Jaguars, only to return for the second half.

The 27-year-old suffered a high-ankle sprain and said after the 27-20 win that he'll "be good to go" this Sunday and will do "whatever I can to be as close to 100%".

Mahomes had a toe injury during the Chiefs' play-off run two years ago, when they lost Super Bowl 55 to Tom Brady's Tampa Bay Buccaneers.

After that game he said "if you're playing football, you have to battle through injuries". He's had to do that in practice this week and has even got some advice from record seven-time Super Bowl winner Brady.

"I have a good relationship with him now," said Mahomes. "Why would you not to want to hear from the 'GOAT', man? It's cool to see the guys you watched growing up talk to you on that type of platform."

Mahomes, who led the NFL with 41 touchdown passes and a career-high 5,250 passing yards this season, said treatment and rehab has been "a full-day thing" all week.

The Chiefs' offensive line has been primed to offer Mahomes greater protection, so he doesn't have to scramble out of the pocket, but right-handed quarterbacks also use their right foot as the base to make their throws.

And although Mahomes has not fully tested his injury this week, he has shown since coming into the league in 2017 that he has the arm to make unorthodox passes when flat-footed or off-balance.

"When we get in the game, you know adrenaline is going to take over and you can make those throws when you need to," he said.

In five seasons as a starter, Mahomes has reached the AFC Championship Game each time and Kansas City are aiming to reach a third Super Bowl in four years.

Yet the Chiefs were upset at home last year by the Bengals, whose surprise run to the Super Bowl ended in a 23-20 loss to the Los Angeles Rams.

Just two years earlier, Cincinnati had the worst record in the league, which ensures they have the first pick in the following season's draft.

With that, they selected Joe Burrow and the quarterback has helped transform the Bengals into a threatening, no-nonsense outfit.

Cincinnati have won all three games against Kansas City over the past two seasons and return to Arrowhead Stadium, hosting the AFC title game for a fifth straight year, for the first repeat of the previous year's match-up since 1988.

"We know them, they know us. It's going to be fun," said Burrow, who has adopted the 'Joe Cool' nickname from legendary 49ers quarterback Joe Montana. "To me, they're still the team to beat and we're coming for them."

Despite playing at a snowy Buffalo last week, the Bengals beat the Bills to dump out the pre-season Super Bowl favourites and claim a 10th straight win.

Knowing a trip to Kansas City was next, Bengals cornerback Mike Hilton said to a TV camera late in the game "we'll see y'all in Burrowhead". He added this week: "It might have stirred a few pots."

It sure has, and it's been used to give extra motivation to Kansas City, whose only loss in their past 12 games was at Cincinnati on 4 December.

"They're throwing a lot of bulletin board material out there," said Chiefs tight end Travis Kelce.

The NFC title game sees the San Francisco 49ers visit the Philadelphia Eagles, who like the Chiefs secured the top seed in their Conference having finished the regular season with a 14-3 record.

That also earned them a bye for week one of the play-offs and gave Jalen Hurts more time to rest the shoulder injury which saw Philly's third-year quarterback miss two games late in the season and drop behind Mahomes in MVP contention.

The Eagles lost both those games but, despite that laboured end to the season, they and Hurts were back to their dominant best as they brushed aside the New York Giants last week.

A trade for receiver AJ Brown was the pick of some astute off-season signings which have allowed Philly, who beat the New England Patriots in Super Bowl 52, to build a well-balanced offence and a solid defence.

However, they now face a San Francisco team with the NFL's best offence and best defence - and they are on a 12-game winning streak.

A mid-season trade for dual-threat running back Christian McCaffrey helped propel the 49ers to a 13-4 finish.

But their past seven wins have been with Purdy as starting quarterback after injuries to Trey Lance and Jimmy Garoppolo, who took San Francisco to Super Bowl 54 before losing to the Chiefs.

Not only is Purdy their third choice but he was also this season's 'Mr Irrelevant', the nickname given to the last man selected in the draft.

The ease with which Purdy has adapted to the NFL has seen the 23-year-old set all sorts of records. Now he aims to top them by becoming the first rookie quarterback to reach a Super Bowl.