KANSAS CITY, Mo. — The opening quarter had become a distant, strange memory by early Sunday evening at Arrowhead Stadium, at which point Patrick Mahomes had concluded his immolation of the Houston Texans. The Kansas City Chiefs began the divisional round of the NFL playoffs with one quarter of catastrophe and slapstick inability to catch or hold on to a football. They ended it with a declaration of their offensive might, an unprecedented avalanche of points amid a sea of red.

On the scoreboard, a message flashed apologizing to fans. It read, in part, “We have run out of touchdown fireworks.”

For most quarterbacks, a three-touchdown playoff deficit is a nightmare. For Mahomes, it is an invitation. After the Chiefs fell behind by 24 early in the second quarter, dredging the torment of the franchise’s playoff past, they scored 41 unanswered points and scored touchdowns on seven consecutive drives. The Chiefs eventually finalized the score at 51-31, riding Mahomes’s five touchdown passes — three of them to tight end Travis Kelce — and 321 yards to a frenzied comeback that became a blowout that became something like art.

“We coming back!” Mahomes screamed toward fans afterward, hopping toward the front row. With the path to their first Super Bowl in 50 years cleared by the Baltimore Ravens’ startling loss Saturday night, the second-seeded Chiefs will host the AFC championship game Sunday against the sixth-seeded Tennessee Titans.

How will the Chiefs’ resurgent defense match up against Titans bulldozer Derrick Henry, especially if defensive tackle Chris Jones cannot return from the injury that kept him sidelined Sunday? Can Mahomes’s talents exploit Tennessee’s defense better than Lamar Jackson’s? Those are the questions of the week rather than the one so often asked in a city that still laments so many squandered playoff games: What just happened?

“Thank God we got Pat Mahomes,” Chiefs defensive end Frank Clark said. “Because if we didn’t, I’m not sure the result would be the same.”

Against a defense that knew he needed to throw for essentially the entire game, Mahomes completed 23 of 35 passes, including 19 of 25 after the first quarter. He skittered in and out of the pocket, flicked darts down the middle to wide receivers and fed Kelce, who finished with 10 catches for 134 yards, everywhere on the field. After a season in which Jackson took over the NFL and probably swiped his MVP honors, Mahomes turned his first playoff game this year into a reminder: He is still the best, most lethal player in the league.

“The way he competes, man, I don’t know if anybody else is like that,” Chiefs backup quarterback Matt Moore said. “He’s not going to give up. The creativity. He’s going to do whatever he can to move the ball and score points. There’s not one thing, I don’t think. It’s just his will to score.”

The Chiefs blasted the Texans with 48 points in less than 30 minutes — “an insane accumulation,” tackle Mitchell Schwartz said. From early in the second quarter to early in the fourth, the Chiefs possessed the ball seven times and scored seven straight touchdowns. On their eighth possession, they reached the Houston 6-yard line and settled for a field goal. The barrage ensured a stress-free finish, the precise opposite of the harebrained beginning.

The first half included: A 54-yard touchdown pass, a blocked punt, a muffed punt, a failed fake punt, a fumbled kickoff return, six touchdown passes, 52 points and everyone you follow on Twitter declaring, “This game is drunk.” The Texans scored 24 consecutive points in the game’s first 19 minutes, and the Chiefs answered with 28 straight in the next 11.

For the first 15 minutes of that madness, the Texans stunned Arrowhead into booing the Chiefs. On their first drive, on third and one from their 46, the Texans lined up their three wide receivers to the left and faked a bubble screen to Will Fuller V. As Chiefs defensive backs swarmed toward Fuller, Kenny Stills bolted downfield, lonely as a tumbleweed. Watson floated him an easy touchdown pass.

Kelce made a crucial third-down drop on Kansas City’s opening drive, which led to linebacker Barkevious Mingo’s blocked punt, which safety Lonnie Johnson scooped and returned for a touchdown. As a torrent of dropped passes stalled Chiefs drives, Tyreek Hill dropped a punt at his 10. Two plays later, Watson’s second touchdown pass bored into the gut of tight end Darren Fells. The Texans added a field goal to make it 24-0 with 10:54 left in the second quarter.

But the Chiefs had Mahomes, and so the Chiefs remained calm.

“You see other teams that don’t have an MVP quarterback and the skill guys we do, and you kind of say, ‘We want to get them into those passing situations,’ ” Schwartz said. “I don’t think anyone approaches us and says, ‘We want to make them throw the ball.’ It definitely plays to a strength of ours in a weird way.”

The game started to turn after Mecole Hardman returned the kickoff to near midfield and Mahomes found Damien Williams on a swing pass for a 17-yard touchdown. It pivoted for good when O’Brien made a curious decision midway through the second quarter.

At his own 33 on fourth and four, O’Brien called for a fake punt, a direct snap to up man Justin Reid. The upside was Houston possessing the ball on its own side of the field. The downside was giving a pyrotechnic offense the spark it needed in front of famously crazed fans.

The Texans realized the downside when Chiefs safety Daniel Sorensen snuffed Reid with an open-field tackle after a two-yard gain.

“We felt like we were not going to be able to punt it too many times today,” O’Brien said. “We felt like we had to manufacture some points, manufacture some yards.”

Three plays later, Mahomes rolled right and hit Kelce for a five-yard touchdown. A potential Texans rout had turned into a 24-14 contest.

In the end, maybe no choice O’Brien made could have countered Mahomes. His greatest moment came at the end of the half. He steered the Chiefs downfield until they reached the Houston 5 with 44 seconds left. Mahomes scrambled and rolled left, waiting . . . waiting . . . waiting for a defender to choose between guarding Kelce in the front of the end zone or rushing at him. When cornerback Bradley Roby stepped forward as Mahomes reached the 5, Mahomes shoveled a pass to Kelce, dragging his toe to prevent it from crossing the line of scrimmage. Replays validated the move, and the Chiefs took a 28-24 lead.

Teammates marvel at Mahomes’s awareness, and some wondered whether the toe drag had been intentional; Moore, for one, said he wouldn’t put it past him. Mahomes chuckled when asked but shook his head, no.

“I knew I was close,” Mahomes said. “I was trying to get [the pass] out as soon as possible.”

Mahomes had brought the Chiefs all the way back, in less time even than it took them to fall behind. Kansas City had been in trouble, but there is a difference between trouble and desperation. One can happen when Mahomes is your quarterback, and the other cannot.

Read below for our in-game updates.