Since the Kansas City Chiefs and Tampa Bay Buccaneers walked off the field following Super Bowl LV, the NFL underwent an offseason of oddities. Franchise quarterbacks demanded trades. Left out of the playoffs, the New England Patriots binged in free agency. Tom Brady aged in reverse.

For all the tremors of the spring and summer, the NFL in Week 1 picked up where it left off: with everybody else trying to surmount the Buccaneers and Chiefs, with Brady and Patrick Mahomes holding the league at arm’s length. Two opponents threw everything at Brady and Mahomes in the two best games of the week, and both limped off the field dismayed.

In other ways, Week 1 disoriented. Jordan Love played quarterback for the Green Bay Packers, but only because somebody needed to take snaps in garbage time after Aaron Rodgers put up just three points. As fans returned to stadiums in full, home teams lost more games than they won. The Patriots were outmuscled and out-executed in the endgame by the Miami Dolphins.

The Texans are in first place, rookie quarterbacks couldn’t win, the NFC West can’t lose, and here is what to know.

The Cleveland Browns are very good and impeccably run. Fast, creative and aggressive might be the three things an NFL team should strive to be above all else. Under the youthful, brainy tandem of General Manager Andrew Berry and Coach Kevin Stefanski, the Browns appear to be elite in all three categories. But so are the Chiefs, and the Chiefs have Mahomes.

That was the difference in the most thrilling game of Week 1. The Browns crafted an intelligent game plan, executed it brilliantly and led the Chiefs, who knocked them out of the playoffs in January, for almost the entire game. Mahomes launched a sidearm fling some 40 yards to Tyreek Hill, the Browns botched a punt, and Mahomes found Travis Kelce in the red zone. The Chiefs, as they so often do, pulled a loss out of the fire and won, 33-29.

It was the kind of game that makes you hope to see it again in January. The Chiefs won, but the Browns were the story — they proved themselves a threat to beat Kansas City later.

It started with a philosophically perfect opening drive. Opponents must be aggressive and keep the ball from Mahomes to beat the Chiefs, and the Browns had the nerve and talent to do it. The Browns eschewed a field goal on fourth and three from the 15, converted and scored a touchdown — then went for two after devouring seven minutes. They went for it on fourth down inside the 10-yard line again on an ensuring drive and scored on a Jarvis Landry jet sweep.

It was not just game management. It was savvy deployment of personnel. The Browns drafted Anthony Schwartz, a wide receiver who runs the 40 in 4.25 seconds, to add more speed. On some of the first touches of his career, Stefanski wielded him on a play-action deep shot for 44 yards and an end-around for 17.

The Browns built a 22-10 halftime lead and led 29-20 early in the fourth quarter. And then Mahomes happened, pushing his record in September to 11-0.

The Browns could feel good even in defeat, aside from the sight of left tackle Jedrick Wills Jr. leaving the field on a cart after hurting his left ankle. They didn’t even have Odell Beckham Jr., who wasn’t ready to return from last year’s torn ACL after sitting out most of the preseason. They still have to find a way to get past the Chiefs, like everybody else, but they might be Kansas City’s biggest threat in the AFC.

Is there reason to worry in Buffalo? A popular Super Bowl pick because of Josh Allen and a high-powered offense, the Bills fizzled at home in a 23-16 loss to the Pittsburgh Steelers. T.J. Watt strip-sacked Allen at the end of the first half and Pittsburgh scored off a blocked punt — and those two plays made the difference.

Pittsburgh’s defense will make plenty of teams look bad, but for Buffalo the performance — which included 5.3 yards per attempt from Allen — hinted at trouble. In their noncompetitive loss in the AFC championship game at Kansas City, the Bills scored 24 with a flurry of late, inconsequential points. They scored 17 against the Baltimore Ravens in the round prior, seven of which came on a pick-six.

That’s three straight poor offensive showings, and it may not be a coincidence. When teams play two safeties deep, the Bills lack a running game that can exploit it. When defenses take Stefon Diggs away with extra help, the Bills’ other wide receivers are revealed as solid complementary players who don’t scare teams much. Diggs’s longest completion Sunday went for 13 yards.

Last year provided evidence that the Bills have the pieces for a top-shelf offense, but recent games suggest the best teams have started to solve them. Buffalo used its first two draft choices on pass rushers to stop opposing offenses. Gregory Rousseau and Carlos Basham will be rendered baubles if the Bills can’t counterpunch against defenses that are figuring out how to take away their explosive plays.

The New Orleans Saints have a championship-caliber defense. As the Saints hosted the Packers in Jacksonville, Fla., in the wake of Hurricane Ida, it was supposed to be about the quarterbacks: Jameis Winston replacing Drew Brees and Aaron Rodgers debuting after an offseason of acrimony (and “Jeopardy!” hosting).

The Saints’ defense overwhelmed the narrative and the Packers, trouncing Green Bay, 38-3, in the worst loss of Rodgers’s career. Winston did not surpass 200 yards, and yet he still threw five touchdown passes on only 20 attempts. Behind an offensive line in desperate need of left tackle David Bakhtiari, who will be out through Week 6 after offseason knee surgery, Rodgers played with uncharacteristic panic. He threw two interceptions, including a terrible pick in the red zone that swung the game, and passed for just 133 yards.

In Brees’s final years, the dirty little secret was that the Saints’ defense carried them. They still have that ferocious defense with pass rusher Cam Jordan and cornerback Marshon Lattimore, and Winston’s ability to throw downfield gives them something they lacked with Brees. It may not be a rebuilding year in New Orleans after all.

Who needs Deshaun Watson? Not the Houston Texans, at least against the Jacksonville Jaguars with Urban Meyer and Trevor Lawrence (three interceptions) making their NFL debuts. After a turbulent offseason drenched in organizational dysfunction, the Texans blew out Jacksonville, 37-21. An 0-17 record seemed in play for Houston this year. The Texans are 1-0.

Watson’s saga — in which he demanded a trade, refused to play for the franchise and subsequently faced accusations of sexual harassment and assault from 22 women — dominated their offseason and training camp. They hired a no-name lifer in Coach David Culley. Jack Easterby retained an alarming amount of control over the franchise.

Don’t plan any parades, but for one week credit Culley. He pulled an excellent, professional effort from an utterly lacking roster amid chaos and ample criticism of his hiring. It helps that the Texans have established veterans — Mark Ingram, Phillip Lindsay, Tyrod Taylor and Brandin Cooks on offense alone. The Texans are not a good team, even if they are alone in first place in the dreadful AFC South. They showed they’ve got pride — and maybe revealed how terrible the Jaguars will be in Meyer’s first season.

Jimmy Garoppolo made a statement. Starting for the San Francisco 49ers for the first time since they traded up to draft his replacement, Trey Lance, Garoppolo dropped a snap on the first drive. He then completed almost every pass he threw in the first half and scored on every other drive before halftime.

Garoppolo had help from Lance, who threw a touchdown pass after Coach Kyle Shanahan inserted him as a goal-line wrinkle on San Francisco’s first scoring drive. Garoppolo finished 17 for 25 for 314 yards and a touchdown, including Deebo Samuel’s nine catches for 189 yards. The Lions did not provide the stiffest test, but Garoppolo was confident and accurate.

The 49ers have the roster to make the Super Bowl. Lance may have the higher long-term ceiling, but the 49ers’ best chance for 2021 is Garoppolo playing well enough to keep the starting job while easing Lance in as a change-up or a red-zone weapon. Garoppolo so far has handled a potentially awkward situation with admirable professionalism. If the 49ers go back to the Super Bowl, it probably will be behind the quarterback who led them there two seasons ago.

The Philadelphia Eagles took a step forward. Philadelphia is talented and deep along both lines, a fact made irrelevant last year as injuries decimated both units, especially the offensive line. Rookie DeVonta Smith (six catches, 71 yards and a touchdown Sunday) gave the Eagles a receiving weapon they desperately needed. Jalen Hurts’s floor is better than the strange hero ball Carson Wentz played last season, and his ceiling is high. A running quarterback combined with new coach Nick Sirianni’s system is a great recipe to steal a win or two early.

The Eagles throttled Atlanta, 32-6, in Arthur Smith’s head coaching debut with the Falcons. Given Washington quarterback Ryan Fitzpatrick’s injury during a home loss, the Eagles can make a case as a legitimate contender to win the NFC East. (And, no, that’s not merely a reaction to one game.)

The rookie quarterbacks were a mixed bag. Mac Jones, Zach Wilson and Lawrence were the three first-round quarterbacks who started Sunday. All of them lost, but with varying degrees of success.

Wilson led the New York Jets to two late touchdown drives, keeping them in it despite scoring no points in the first half during a 19-14 loss to the Panthers. Lawrence passed for 332 yards and three touchdowns but also threw three interceptions against the Texans, including a bad one from his own end zone shortly before halftime. Jones played with poise and accuracy against Miami’s constant blitzes, but he needs improvement in the red zone and more help from his running backs — Damien Harris’s fumble cost him the chance to lead a game-winning drive for the Patriots late in the fourth quarter.

The Tennessee Titans were the most disappointing team of Week 1. The Titans had two assignments this offseason coming off a first-round loss to the Baltimore Ravens: fix an atrocious defense and maintain a high-powered offense after losing coordinator Smith to Atlanta. They sputtered utterly on both counts as the Arizona Cardinals smoked them, 38-13, in Nashville.

Kyler Murray shredded Tennessee’s secondary for 289 passing yards and four touchdowns, and Chandler Jones manhandled left tackle Taylor Lewan on his way to five sacks.

The Cardinals’ victory helped the NFC West go 4-0 in Week 1, winning by an average of 16.25 points. After one week, as expected, it looks like the best division in football.

Dak Prescott is all the way back. The Dallas Cowboys may have lost their opener Thursday night, but few teams had a more promising Week 1. Coming back from major ankle surgery and a shoulder injury, Prescott excelled in his first game after signing a four-year, $160 million contract extension. He forced every ounce of greatness from Brady, leading a go-ahead drive in the final minutes and throwing for 403 yards.

In his past six games — the five before he got hurt last year and Thursday night — Prescott has thrown for 2,259 yards. That means that, for more than a third of an NFL season since Jason Garrett was coach, Prescott has averaged 376.5 passing yards. He’s one of the best players in the NFL, and if his shoulder holds up and a young, fast defense comes together at all, the Cowboys will be competitive against anybody.