By Michael Hurley, CBS Boston

BOSTON (CBS) — The Kansas City Chiefs suffered a loss on Sunday night. With it died one very stupid dream for Patrick Mahomes.

The Chiefs’ quarterback had stated this offseason that coming off last year’s Super Bowl loss, he and his Kansas City brethren were looking to go undefeated in 2021.

“The only record I have my eyes set on breaking, which would be new this year, would be going 20-0,” Mahomes told Bleacher Report in the spring. “It’s not really a record to be broken, I guess you would say. … Being able to go 20-0 and being the first one to do that, that would be awesome.”

Alas, that dream lasted all of two weeks in the 2021 season.

Mahomes and the Chiefs’ offense was electric as usual on Sunday night in Baltimore, with the QB throwing for 343 yards and three touchdowns … without really breaking a sweat. His touchdown pass to Demarcus Robinson was rather ridiculous.

The Chiefs looked to be in control of the game when they took a 35-24 lead in the third quarter, when zero Ravens players seemed willing or capable of tackling Travis Kelce on his 46-yard catch-and-run for a TD.

Yet the Kansas City run defense had some major problems handling Lamar Jackson and Co. Jackson ran for 107 yards and two touchdowns himself, while Ty’Son Williams had 77 yards, Latavius Murray had 36 yards and a touchdown, and Devonta Freeman had 29 yards on the ground.

Mahomes threw an ill-advised interception late in the third quarter …

Patrick Mahomes throws an interception against the Ravens. (Photo by Todd Olszewski/Getty Images)

… and rookie Odafe Oweh forced a fumble when the Chiefs were cozying up for a game-winning field goal attempt:

The Ravens then went for it on fourth-and-1 on the ensuing possession, allowing them to run out the clock.

When that clock hit zero, the Chiefs took their first L of the season — and Mahomes took the first L in September of his entire career. (That was also the first September interception of his career.)

Of course, as anyone in New England would attest, going undefeated is not all it’s cracked up to be. It surely adds a lot of pressure come playoff time, and even Bill Belichick admitted in that HBO special with Nick Saban that his 2007 Patriots would probably have been better-served to have lost a game or two along the way.

Alas, Mahomes wanted that perfect record anyway. Some in the media believed it was realistic.

Yet the odd, misguided dream of going 20-0 has eluded the Chiefs this time. There’s always next year.