Coach Andy Reid helped the Chiefs overcome a stretch where they lost five of eight games and has them a win away from back-to-back Super Bowl titles. Reed Hoffman/Associated Press

Andy Reid celebrated his 25th season as a head coach with a masterful performance on the sideline and in the locker room.

The Kansas City Chiefs are one victory away from becoming the first NFL team in 19 years to win back-to-back Super Bowls. They’re in Las Vegas to face the San Francisco 49ers despite a midseason slump that could’ve ruined their repeat hopes.

Reid kept them steady.

This isn’t the best team Reid has coached but it just might be his best coaching job.

Sure, he still has Patrick Mahomes. But the two-time NFL and Super Bowl MVP had a subpar season by his lofty standards. He didn’t get much help from his wide receivers at times. They led the league in drops. Mahomes once again counted on star tight end Travis Kelce, who had a slight dip in production to go with a massive increase in global attention due to his relationship with Taylor Swift.

Reid made sure Kelce’s newfound celebrity status didn’t become a distraction.

After starting 6-1, the Chiefs lost five of eight games. At 9-6, they even had a shot to miss the playoffs and ended up with their most losses since 2017.

No chance Reid would let them stumble further. The Chiefs won the next two games to clinch their eighth straight AFC West title and have kept on winning in the playoffs, beating Miami at home in the wild card round, going on the road to beat Buffalo in the divisional round and No. 1-seeded Baltimore in the AFC championship game.

“Coach Reid just challenging every single person in this building to up the ante just one more step and just keep taking it up a notch every week from here on out,” Kelce said. “That’s why we love the big guy. You never fall astray from that kind of mentality no matter how many losses you have, no matter how close the games are and you’re just not finishing them. Coach Reid does a great job of re-channeling that mindset every single week and presenting a challenge against the defense or the offense or just the team we’re going against in the near future. This week, no better time to challenge everybody in that building. He’s got everyone fired up.”

Reid credits Mahomes and Kelce for their leadership, setting the tone for how the team should practice. He also praised General Manager Brett Veach for adding players who fit that mentality.

“You’re not going to dog it with Pat Mahomes going full speed, Kelce going full speed,” Reid said. “They’re not going to allow you to do that first of all. Then you watch them, and you watch how they practice, you know it’s not a fit if they can’t do that. Brett is not going to bring in guys that dog, jog, whatever you want to call it.”

The Chiefs lost a Thursday night game at Denver to a team that came in 2-5. Two weeks later, they lost a Super Bowl rematch at home to Philadelphia when Marquez Valdes-Scantling dropped what should’ve been a go-ahead touchdown pass late in the game.

There was another prime-time loss at Green Bay on Dec. 3 followed by a loss at home to the Bills when Kadarius Toney’s TD off a lateral from Kelce was wiped out by an offside penalty on Toney.

A loss to the Raiders on Christmas was the third straight defeat at home and led Reid to make some adjustments. The offensive coaching staff decided to simplify a complex offense and five wins later the Chiefs are back in the Super Bowl for the fourth time in five years.

“I think it gave our guys a nice little – for (lack of) a better term a wakeup call that, ‘Listen we need to step things up here. Things aren’t just going to fall in our lap,’ ” Reid said of the loss to Las Vegas. “We’re taking everyone’s best shot, here’s a team that went through some adversity, and they stepped up and were able to present themselves like they did. We were able to learn from it and move on. I felt all along though (that) we had the ability to do that, like I said, we need a little kick in the tail there.”

Reid has already won two Super Bowls and more games than any coach in the history of the Chiefs and the Philadelphia Eagles. He’ll end up in the Pro Football Hall of Fame win or lose against the 49ers.

If the Chiefs win, it’ll be hard to argue that the 65-year-old Reid isn’t getting even better with age.