The Miami Dolphins stunned the New England Patriots 27-24 on Sunday, allowing the Kansas City Chiefs to seize a first-round playoff bye with a 31-21 triumph over the Los Angeles Chargers.
The heavily favored Patriots' loss on their home field at Gillette Stadium, coupled with the Chiefs' win, means Tom Brady and the reigning Super Bowl champions will play in the wild card round for the first time since 2009.
"We didn't play the way we were capable of and we got beat," said a downbeat Brady, adding "too many bad mistakes" cost the Pats.
"Now we've got to play next week -- and we've got to play a lot better next week."
The Patriots' first-round opponents had yet to be decided, with two remaining playoff berths up for grabs and seedings in both the American Football Conference and National Football Conference still to be determined on the final day of the regular season.
Green Bay locked up an NFC first-round bye in dramatic fashion in Detroit, where Mason Crosby kicked a 33-yard field goal as time expired to lift the Packers to a 23-20 victory over the lowly Lions.
With quarterback Aaron Rodgers struggling, the Packers trailed by two touchdowns in the second quarter, and didn't take the lead until Crosby came through.
The New Orleans Saints did all they could to assure themselves of a first-round bye, crushing the Carolina Panthers 42-10.
But the Packers' victory left the Saints awaiting the outcome of the San Francisco-Seattle clash for the NFC West division title later Sunday, in which a win would give the 49ers the bye.
- 'Bad pass' -
The Patriots, who have never won a Super Bowl without the benefit of a week's rest in the first round, looked set to escape with a victory when James White pulled down a screen pass and ran for a 13-yard touchdown that put New England up for the first time with 3:53 remaining.
But the Dolphins, long eliminated from playoff contention, marched 75 yards in three minutes and quarterback Ryan Fitzpatrick found tight end Mike Gesicki for the winning TD with 24 seconds left.
Brady struggled much of the day, completing 16-of-29 passes for 221 yards and two touchdowns.
Brady's first TD pass of the day moved him past Peyton Manning into second on the NFL's all-time touchdown pass list headed by Drew Brees.
But his pass intercepted by former teammate Eric Rowe in the second quarter was returned for a touchdown that gave the Dolphins a 10-3 lead.
"It was just a bad throw," the 42-year-old superstar said, insisting that he had no physical problems on the day.
New England's top-ranked defense allowed a season-high in yards to a Dolphins offense led by Fitzpatrick -- who threw for 320 yards and a touchdown and also ran for a TD.
Patrick Mahomes and the Chiefs didn't waste the opportunity provided by the Pats' defeat, locking in the AFC second seed and a bye with a gritty win over the Chargers.
Los Angeles led 14-10 after an early third-quarter touchdown, but Chiefs rookie wide receiver Mecole Hardman returned the ensuing kickoff 104 yards for a touchdown to ignite a Kansas City rally.
Running back Damien Williams added an 84-yard TD run for the Chiefs.
Shocker: New England quarterback Tom Brady is sacked by Miami's Trent Harris in the Dolphins' upset win over the Patriots on the final day of the 2019 NFL regular season
Comeback: Davante Adams of the Green Bay Packers celebrates a touchdown with teammate Jake Kumerow in the fourth quarter of the Packers' NFL victory over the Detroit Lions
Miami's Mike Gesicki catches the game-winning touchdown in the Dolphins' upset win over the New England Patriots
Kansas City rookie wide receiver Mecole Hardman escapes a tackle attempt by Jatavis Brown in the Chiefs' NFL victory over the Los Angeles Chargers