Atlanta and Pittsburgh have clinched NFL playoff berths while fellow division leaders Indianapolis, Kansas City and Philadelphia won key games to seize control of their destiny.
Matt Ryan completed 20 of 35 passes for 174 yards and three touchdowns to spark Atlanta past host Seattle 34-18, stretching the Falcons' win streak to eight games, their longest since 1998, and their NFL-best record to 12-2.
The Falcons became the first National Conference team to secure a playoff spot and can clinch the NFC South title, their first division crown since 2004, and a home-field edge in the playoffs by defeating New Orleans next week.
"It is going to be a great atmosphere next week," Ryan said. "I think everybody is looking forward to it."
Pittsburgh backed into the post-season as quarterback Mark Sanchez ran for the first touchdown in 12 quarters for the New York Jets' offensive unit in a 22-17 victory over the Steelers, their first-ever triumph at Pittsburgh.
"It was a relief," Jets tackle Wayne Hunter said. "It really was a relief and a big burden off our shoulders."
An hour after the loss, the Steelers (10-4) were told by the NFL that based on a complicated set of tie-breakers, they had clinched a playoff spot despite the defeat.
Victories over struggling Carolina and Cleveland to end the season will give them the division crown and a first-round playoff bye as well.
"We've just got to win two more games, very winnable games, teams we match up well against," Steelers safety Ryan Clark said.
Indianapolis, trying to avoid missing the playoffs for the first time since 2001, beat Jacksonville 34-24 to pull even with the Jaguars atop the AFC South at 8-6. Their tie-break edge means they need two wins for the division title.
"It's a good win but it's just one game," Colts quarterback Peyton Manning said. "We have to be able to come out and do it again next week."
The Colts denied the visiting Jaguars their first division crown in 11 years in their showdown after Tyjuan Hagler of the Colts scooped up the ball on an onside kick attempt and ran 41 yards for the decisive touchdown.
Philadelphia scored 28 points in the last 7:28 to stun the New York Giants 38-31, as Michael Vick threw for two touchdowns and ran for another in a rally that set up DeSean Jackson's 65-yard punt return touchdown on the final play.
"This is one of the greatest comebacks of my career, being down by such a huge deficit," Vick said. "It's outstanding."
Vick, who sqandered his first bid for NFL stardom with a dogfight gambling conviction that sent him to prison, threw for 242 yards and three touchdowns and led all rushers with 130 yards.
Jackson fumbled the punt on the last play but picked up the ball, raced past the onrushing Giants defenders and down the sidelines, then danced along the goal line until time expired before crossing into the end zone.
"I've never been around anything like this in my life," Giants coach Tom Coughlin said. "It's about as empty as you get to feel in this business."
Matt Cassel, playing 11 days after an emergency appendectomy, threw for 184 yards to lead Kansas City past St. Louis 27-13. The Chiefs improved to 9-5 and remained one game ahead of San Diego in the AFC West.
"Everything felt good," Cassel said. "And a win makes it feel better."
The AFC playoff picture cleared behind already-in New England and Pittsburgh with the Jets and Baltimore joining Indianapolis and Kansas City as the teams to beat with the Jaguars and San Diego in pursuit.
Baltimore's Ray Rice ran for 153 yards and scored two touchdowns to spark the Ravens over New Orleans 30-24, snapping a six-game win streak for the reigning Super Bowl champion Saints.
"It just don't get no better," Baltimore linebacker Ray Lewis said.
In the NFC, Atlanta, Philadelphia and New Orleans have the edge in the playoff hunt with Chicago and Green Bay fighting for the NFC North crown while Tampa Bay and the Giants lurk for wild-card spots.
Then there is the NFC West, where co-leaders Seattle and St. Louis lost on Sunday, each falling to 6-8 to ensure the playoff-bound division champion will not have a winning record.
Green Bay fell to 8-6 with a 31-27 loss at New England, leaving the Packers 1 1/2 games behind Chicago in the division and level with Tampa Bay and one game behind the Giants in the fight for the last playoff spot.
Chicago will visit Minnesota on Monday in a game to be played in an outdoor collegiate stadium rather than the Vikings' usual domed home, which is still out of commission after heavy snow collapsed the inflatable roof a week ago.