The NFL returned Thursday, the Detroit Lions and defending Super Bowl-champion Kansas City Chiefs kicking off the 2023 season with an entertaining curtain-raiser – a 21-20 upset won by the Lions.

Naturally, given the importance of every NFL game relative to regular-season contests in other sports, the winners and losers on a given day or night tend to run much deeper than the final verdict on the scoreboard. That also held true at Arrowhead Stadium, with quite a cast of characters – and bystanders – impacting the final result. So let’s dig a little deeper as we discern the evening’s winners and losers:

WINNERS

Jared Goff: The Lions quarterback, who didn’t play a lick in preseason, pretty much picked up where he left off from his 2022 Pro Bowl effort, passing for 253 yards and a TD while effectively protecting the ball.

Chiefs defense: The unit was without All-Pro DT Chris Jones, his ongoing holdout landing him at an Arrowhead Stadium suite to watch the action, and suspended DE Charles Omenihu, one of the team’s primary offseason signings. Nevertheless, K.C. held up fairly well, surrendering just two touchdowns.

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AFC hopefuls: No better outcome for title aspirants like the Jets, Bills, Bengals, Ravens, Jaguars and a few others than watching the champs stumble out of the blocks in what promises to be a hypercompetitive conference.

Lions rookies: They didn’t necessarily take over the game, but you wouldn’t expect players making their professional debuts to do as much. Still, RB Jahmyr Gibbs (60 yards on nine touches), TE Sam LaPorta (5 catches, 39 yards) and DB Brian Branch (50-yard pick-six) all flashed the ability that projects them to be big-time contributors. And presumably Branch, who exited the game before the fourth quarter with cramping, will be OK for Week 2.

1-0 start for Detroit: Now in his third season, head coach Dan Campbell won his opener for the first time. The Lions started 0-10-1 in 2021 and 1-6 last year prior to strong finishes but could finally be on the way to their first NFC North crown in club history.

LOSERS

0-1 start for Kansas City: Patrick Mahomes lost in Week 1 for the first time since becoming the Chiefs’ QB1 in 2018. It may not seem like a big deal, but the ramifications could be huge for a team seeking to become the first to win back-to-back Lombardi Trophies in 19 years. Since the NFL expanded to 32 teams in 2002, roughly half the teams that win their openers make the playoffs … while teams that start 0-1 qualify for postseason about a quarter of the time. Prior to Thursday, the Chiefs had won their last eight season debuts overall.

Mahomes’ Week 1 numbers: His fantasy owners will certainly be miffed. Thursday was the first time in the two-time MVP’s career that he didn’t throw for at least three TDs out of the chute. He also served up his first Week 1 INT, the one Branch took back for a TD – albeit off a deflection – and his 77.5 QB rating was his first that fell short of 100.0.

Sequels: Mahomes’ only NFL-related visit to the LA Coliseum in 2018 was far more memorable than Goff’s first trip to Arrowhead. Sure, this game was a welcome arrival for NFL fans. But anyone who saw Goff’s Rams beat Mahomes’ Chiefs 54-51 five years ago in their only previous meeting – the only game in league history with two teams both scoring half a hundred – won’t forget what was arguably the greatest regular-season game of all time.

Defending Super Bowl champs: That’s two years in a row they’ve lost on opening night. Hard to believe the Chiefs’ season will go as poorly as the Rams’ historically bad 5-12 title defense in 2022 but obviously not an ideal start.

Kansas City’s young wideouts: Being without All-Pro TE Travis Kelce obviously had a cascading effect, but no Chiefs wide receiver had more than three receptions. Skyy Moore and Kadarius Toney, presumably the team’s top two at the position moving forward, combined for one catch for 1 yard – Toney committing three egregious and costly drops.

Kansas City’s new offensive tackles: The Chiefs opted to switch the starting bookends (LT Orlando Brown Jr. and RT Andrew Wylie) from their Super Bowl 57 lineup, signing LT Donovan Smith and RT Jawaan Taylor instead. And while they didn’t allow a sack of Mahomes, both blockers incurred penalties (they combined for 19 infractions with their previous clubs in 2022) on the team’s final drive, which ended in failure when HC Andy Reid went for it on fourth-and-25. Taylor’s questionable alignment throughout the game and quick get-off – he was flagged for a false start on K.C.’s penultimate snap – are sure to draw closer scrutiny from opponents (and refs?) moving forward.

‘Enter Sandman’: The Metallica classic has become part and parcel of one of college football’s best traditions, when Virginia Tech’s players take the field at Lane Stadium. It was also a fantastic way to signal the entry of New York Yankees reliever Mariano Rivera, the greatest closer in baseball history. The Chiefs emerged from their tunnel right before kickoff as those heavy metal guitars and drums built toward takeoff … yet the whole experience fell flat with the Arrowhead crowd. Let’s leave "Sandman" to the college crew, K.C. fans, and you stick to your signature in-game din.

Chiefs offense: The loss of Kelce (hyperextended knee) probably couldn’t be understated – and was far more penal than Jones’ absence – given his on-field mind meld with Mahomes. And it was clear that Kansas City’s disjointed attack – Kelce was hurt just days before the game, which was also the first since the departure of former offensive coordinator Eric Bieniemy – just didn’t have sufficient time to adapt on a night when it posted 316 yards and two TDs. In the previous five seasons, K.C. averaged 37.8 points but barely managed half that much against the Lions while failing to convert all seven of their third-down attempts after halftime. Not nearly good enough.

Follow USA TODAY Sports' Nate Davis on X, formerly Twitter @ByNateDavis.