The Kansas City Chiefs took another step toward a Super Bowl title defense Saturday, routing the Miami Dolphins 26-7 at frigid Arrowhead Stadium in the first round of the NFL playoffs.

Houston kicked off wildcard round action with rookie quarterback C.J. Stroud guiding the Texans to a 45-14 victory over the Cleveland Browns that ended veteran Joe Flacco's comeback story.

Kansas City quarterback Patrick Mahomes threw for 262 yards and a touchdown, Harrison Butker kicked four field goals and the Chiefs defense kept Miami's potentially explosive offense in check, the hosts shrugging off brutally cold conditions.

It was minus-4 Farenheit (-20C) at kickoff with the wind chill making it feel even colder, the NFL calling it the fourth-coldest game in league history.

Pop icon Taylor Swift turned out to cheer boyfriend Travis Kelce, wearing a Chiefs-themed down coat emblazoned with the star tight end's number 87, and Chiefs coach Andy Reid's trademark mustache was frozen by half-time.

"We knew it was going to be cold, but all week we were preaching let's come in there with that fire and just get after it and see what happens," said Mahomes, who hit rookie Rashee Rice for a touchdown on the first drive of the game.

Kelce had seven catches for 71 yards and Isiah Pacheco ran 23 times for 82 yards and a touchdown.

The cold might have been a factor when Mahomes's helmet cracked when he took a hit in the second half and it took some time to adjust a replacement kept on the sideline.

"It was, like, frozen," Mahomes said of the replacement helmet, which had to be warmed up before he could wear it.

Mahomes shook off the distraction and the Chiefs reached the divisional round of the playoffs for the sixth straight season.

Meanwhile, the Dolphins' dynamic offense never fired as Kansas City's defense kept Miami quarterback Tua Tagovailoa under constant pressure.

Wide receiver Tyreek Hill had a 53-yard touchdown catch but was otherwise kept in check by his former team and the Dolphins finished with just 264 total yards.

In Houston, Stroud continued his remarkable debut season, throwing three first-half touchdowns to outshine Flacco, the 38-year-old Super Bowl winner who was brought out of semi-retirement by the Browns after they lost three quarterbacks to injury and propelled them into the post-season.

- Special Stroud -

Stroud completed 16 of 21 passes for 274 yards with no interceptions and the Browns defense never got to him for a sack.

"Just to have another week to go at it with my brothers is a blessing," said Stroud, who at 22 years and 102 days became the youngest quarterback to win a playoff game, passing Michael Vick, who was 22 and 192 days old when he led the Falcons past the Packers in 2002.

"He's special, a special young man," Texans coach DeMeco Ryans said of Stroud. "Continues to shine no matter how big the moment is."

Stroud connected with Nico Collins for a touchdown that put Houston up 10-7. He hit Brevin Jordan for a 76-yard TD and his 37-yard strike to Dalton Schultz put the Texans up 24-14 at halftime.

Then Houston's defense took over.

Flacco, who was without a team until late November after being released in the off-season by the New York Jets, threw for one first-half touchdown but had two second-half interceptions returned for touchdowns.

He was under pressure when he unleashed a pass that was intercepted by Steven Nelson, who gleefully charged 82 yards for a touchdown.

Then a Flacco pass intended for Harrison Bryant was snaffled by Christian Harris, who returned it 36 yards for a score.

Texans running back Devin Singletary put it away early in the fourth with a 19-yard touchdown run.

"We've got to just keep it going," Stroud said, heaping praise on his teammates. "There's no me without my teammates, my O-line, my tight ends, my running backs, receivers and my defense. We all put it together.