The Kansas City Chiefs clinched the top seed in the NFL's AFC and the only play-off bye in the conference with a 17-14 win over Atlanta Falcons.
Patrick Mahomes threw a 25-yard touchdown pass to Demarcus Robinson with less than two minutes remaining as the Super Bowl champions took the lead.
The Chiefs had to watch as the Falcons' Pro Bowl kicker Younghoe Koo pushed a 39-yard field-goal attempt wide with 14 seconds left that would have tied the game.
The victory was an NFL record seventh straight one-possession game for the Chiefs (14-1) and they matched a franchise record with their 10th straight win.
The Seattle Seahawks claimed the NFC West title with a 20-9 victory over the Los Angeles Rams while Washington blew their first chance at securing the NFC East after a 20-13 loss to the Carolina Panthers.
Ben Roethlisberger overcame a month-long malaise with three second-half touchdown throws as the Pittsburgh Steelers locked up the AFC North title with a 28-24 win over the Indianapolis Colts.
Listless and lifeless during a three-game losing streak that followed an 11-0 start, Pittsburgh (12-3) somehow got it together against the play-off chasing Colts (10-5) - who let slip a 17-point third-quarter lead.
The Baltimore Ravens beat the New York Giants 27-13 to move ahead of the Colts in the AFC wild-card hunt.
With a victory in Cincinnati next week, the Ravens (10-5) will earn a play-off berth for the third year in a row.
After their 23-16 defeat to the lowly New York Jets, the Cleveland Browns will need to beat the Steelers next Sunday to end the NFL's longest play-off drought.
The Jets (2-13) sealed their second straight victory while the Jacksonville Jaguars lost 41-17 to the Chicago Bears to secure the No.1 pick in the next draft - which they will almost certainly use to snare quarterback Trevor Lawrence.
The Bears can make the NFC playoffs for the second time in three years by beating the Green Bay Packers next week at home.
The Dallas Cowboys stayed alive in the NFC East play-off race with a 37-17 defeat of the Philadelphia Eagles while the Los Angeles Chargers and Cincinnati Bengals also won.
Aaron Rodgers threw four touchdown passes, three to DaVante Adams as Green Bay's defence kept the NFL's highest-scoring offence in check during a 40-14 beating of the Tennessee Titans at snowy Lambeau Field.