Within the span of a single game on Sunday, we saw one team’s best case scenario for their young quarterback play out and the other team’s biggest nightmare come to pass. In the Kansas City Chiefs’ 38-27 win over the San Francisco 49ers, Patrick Mahomes, in his home debut at Arrowhead Stadium, beat out a record set by one of the game’s all-time greats. However, this triumph was overshadowed by the sight of San Francisco quarterback Jimmy Garoppolo being carted off the field in what is feared to be an ACL injury (on Monday afternoon, the 49ers confirmed the 26-year-old will miss the rest of the season).

The Chiefs have now started their season 3-0 with much of the credit rightfully going to Mahomes, in his first full year as a starter. He passed for three touchdowns on Sunday, increasing his total to 13, the most by any player in the first three games of the season. He surpassed the 12 thrown by Peyton Manning for the Denver Broncos in 2013 and all Manning did that year was set a new single-season record for most TDs in a year with 55. Oh, and Mahomes has yet to throw his first pick.

Now, it needs to be noted the Mahomes has a remarkable number of weapons to work with: tight end Travis Kelce, wide receivers Sammy Watkins and Tyreek Hill and running back Kareem Hunt. Plus, head coach Andy Reid deserves credit for drawing up plays that get the most out of his young quarterback. Still, none of that should take away just how impressive Mahomes has been just four games into his professional career.

It’s been a dream-like beginning for Kansas City, with Mahomes rightfully becoming the major storyline of the young NFL season. Still, there’s reason to be skeptical about the Chiefs’ start. Yes, that’s partly because you can’t expect a first-year quarterback to keep up this record-setting pace even with the astounding supporting cast he has, but mostly because the Chiefs’ defense remains a major question mark. The Chiefs had a 35-7 lead at one point in the game, only to allow San Francisco to make a game of it late.

This continues a worrisome trend for the team. The 27 points the Chiefs allowed San Francisco to score were the fewest they’ve allowed so far this season. The Los Angeles Chargers scored 28 points against them in the opener and the Pittsburgh Steelers nearly pulled off a comeback win in Kansas City’s Week 2 win, which ended up with the ridiculous final score of 42-37. This offense might be capable of scoring 30+ points per game, but that doesn’t equal a sustainable gameplan

That said, they have a lot less to worry about than the 49ers. It was just last season that Garoppolo was on the receiving end of the accolades that Mahomes has been getting this year. After ending the season by going 5-0 with the 49ers following a trade from the New England Patriots, Garoppolo showed enough promise to warrant the Niners handing him a five-year, $137.5m contract in the offseason. So it must have been horrifying for fans to watch their young franchise player crumple to the ground in the fourth quarter.

Jimmy Garoppolo goes down. Photograph: Jay Biggerstaff/USA Today Sports

The 49ers were struggling to start the season even with Garoppolo, and they’re now 1-2 following this loss. It’s hard to imagine them turning this season around without him. Garoppolo’s backup is the unfortunately named CJ Beathard, who has thrown four touchdowns to six interceptions in seven NFL games.

It’s difficult to think of a game that better illustrates just how quickly fortunes can change in the NFL than Sunday’s contest. The most exciting young quarterback in the league celebrated breaking a record by one of the league’s all-time greats, while last year’s best regular season story crumpled to the ground in a freak injury. Never forget this is a cruel sport.

Co-MVPs of the week

Matt Ryan (QB, Atlanta Falcons) and Calvin Ridley (WR, Atlanta Falcons). The Chiefs aren’t the only team that needs to worry about having amazing offensive performances wasted by a not entirely trustworthy defense. The Atlanta Falcons’ Matt Ryan threw for five touchdowns (and no interceptions) against the New Orleans Saints, for a total of 374 yards. Wide receiver Calvin Ridley caught three of those touchdowns and went off for 146 yards. The Falcons scored 37 points… and lost in overtime. A tough loss for the teams but these two did all they could do.

Video of the week

For the second straight week, Green Bay Packers linebacker Clay Matthews was hit with a questionable roughing the passer call, this time on Washington’s Alex Smith. Unlike last week, where the call negated a game-ending interception and allowed the Minnesota Vikings to tie up the game, the Packers were able to force a punt around. Ultimately, it wasn’t a factor in Green Bay’s 31-17 loss, but Matthews has to start wondering what exactly he’s allowed to do to the quarterback without getting a whistle.

This is a foul for roughing the passer - the defender lands “with all or most of the defender’s weight” on the passer. Rule 12, Section 2, Article 9(b): https://t.co/s9YKN8NLuT #GBvsWAS pic.twitter.com/ei2QZkvvzx — NFL Football Operations (@NFLFootballOps) September 23, 2018

Stat of the week

6,301. That’s the number of career completions by the New Orleans Saints’ Drew Brees, a new NFL record. The Saints, meanwhile, beat the Atlanta Falcons 43-37 in overtime when Brees ran in to score the winning touchdown. He can do it all, it seems.

Quote of the week

“When you need precision decision making you can’t count on a black quarterback.” - Now resigned Texas school superintendent Lynn Redden on Houston Texans quarterback Deshaun Watson.

There have been very few beliefs in the history of the NFL that have been more pervasive or more harmful than the idea that African American quarterbacks lack the skill-set to succeed at their position. As Vice Sports’s Sean Newell has pointed out, these ideas reflect stereotypes that continue to affect how black athletes, in general, are seen and evaluated, detailing how they “often get short shrift as physical marvels, beneficiaries of God-given talent. It not only discredits their intelligence, but all the hard work it takes to make it as a professional athlete.”

Watson accumulated 385 passing yards during the Houston Texans 22-27 loss to the New York Giants on Sunday, including two touchdown passes to go along with a single interception. Watson’s only reaction to Redden’s comments was “That’s on him - let peace be with him. I’m all about love.” In total, the five African American quarterbacks who started games on Sunday threw 11 touchdowns to three interceptions. Sounds like pretty good precision to us.

Elsewhere around the league

• Remember earlier this year when New England Patriots tight end was contemplating retirement, perhaps even to try his hand at becoming an actor? It turns out that Gronk might be a tad craftier than we might think, as it was apparently all a ruse to avoid being traded to the Detroit Lions. This all leaked out, to nobody’s surprise, right before the Patriots and Lions were set to face off against each other on Sunday Night Football, which ended in victory for Detroit. That result means that both teams are now 1-2. Pats fans shouldn’t panic just yet, they got off to a slow start last season and ended up in the Super Bowl.

New England head coach Bill Belichick, left, and Detroit counterpart Matt Patricia meet after the Lions’ double-digit win. Photograph: Rick Osentoski/AP

• Welcome back Carson Wentz! The Philadelphia Eagles quarterback led his team on a late game-winning 17-play drive over the Indianapolis Colts, securing a 20-16 win. The Eagles improved their record to 2-1.

• The Carolina Panthers beat the Cincinnati Bengals 31-21, bumping up their record to 2-1. They got some help from Englishman Efe Obada, who had an interception, a fourth-quarter sack and two QB pressures on the Bengals’ Andy Dalton. Not a bad debut for someone who didn’t play college football, and was briefly homeless as a child.

Efe Obada entered the NFL through the NFL International Pathways Program. Photograph: Don Wright/AP

• Have we had the upset of the year already? The 0-2 Buffalo Bills came into Sunday looking like they were playing for the top pick in the draft, the 1-0-1 Minnesota Vikings have their eyes set on the playoffs. Minnesota was favored by 17 points. By the third quarter, the Bills were somehow up 27-0. A late touchdown by a thoroughly humiliated Kirk Cousins, who was sacked four times in the game, made the score 27-6.

• JJ Watt, the most dominant defensive player in the NFL before injuries took their toll, recorded his first sack in 735 days during the Houston Texans loss to the New York Giants. He followed it up with another two – the only other players with three sacks in a game this season are Von Miller … and Watt’s brother TJ. The Texans were expected to make an impact this season with two of the most talented players in the league – Watt and Deshaun Watson – returning from injury, but after Sunday’s loss they are 0-3.