A day after the shocking suicide of linebacker Jovan Belcher, who also shot and killed his girlfriend, the Kansas City Chiefs beat the Carolina Panthers 27-21 in front of a subdued crowd at Arrowhead Stadium.
The victory ended an eight-game losing streak, but there was little mood of celebration for a team coming to terms with yesterday's tragic events.
Belcher had shot his girlfriend multiple times before driving to the team's practice facility where he killed himself in front of coach Romeo Crennel and general manager Scott Pioli. Belcher was 25.
Hours after the incident, the Chiefs players and coaches made the decision that today's game would go ahead.
When it did, Brady Quinn threw for 201 yards and two touchdowns, and Jamaal Charles collected 127 yards on the ground to lead the Chiefs to an emotional victory.
Cam Newton led Carolina by throwing for 232 yards and three touchdowns.
The New England Patriots clinched the AFC East title with a 23-16 victory over the Miami Dolphins but it was far from a polished performance.
Dolphins penalties accounted for most of New England's scoring as Tom Brady had an off-day, and Miami also had a touchdown chalked off as they proved their own worst enemy.
Brady threw for 238 yards, but was sacked four times and tossed an interception.
It was a sixth straight win for the Patriots, who moved to 9-3.
The Houston Texans secured their play-off berth with a 24-10 win over the Tennessee Titans.
The defence was the key as rookie linebacker Whitney Mercilus had two sacks and a fumble recovery, and the Texans forced six turnovers.
Their 11 wins this season is a franchise record.
Morgan Burnett twice intercepted Christian Ponder in what proved pivotal moments as the Green Bay Packers saw off the Minnesota Vikings 23-14.
The Vikings were inspired by Adrian Peterson, who returned to the kind of form he used to show before blowing out his knee a year ago by rushing for 210 yards.
But it was all for nought as Ponder tossed costly picks that Green Bay turned into points.
It was a vital win for the Packers (8-4) in the NFC North title race as they caught the Chicago Bears, 23-17 losers in overtime to the Seattle Seahawks in the Windy City.
Russell Wilson threw a 13-yard touchdown pass to Sidney Rice in overtime to take the win.
Robbie Gould had kicked a field goal as time expired to send the game to overtime.
Andrew Luck's 14-yard touchdown pass to Donnie Avery as time expired capped a dramatic comeback for the Indianapolis Colts as they beat the Detroit Lions 35-33.
The Lions had led by 12 in the fourth quarter but the Colts came storming back to stay in control of the AFC wild-card race.
Ryan Fitzpatrick threw for 112 yards and two touchdowns as the Buffalo Bills stayed alive, if barely, in the playoff race with a 34-18 win over the Jacksonville Jaguars.
The New York Jets' third-string quarterback Greg McElroy did just enough to lead his side to an attritional 7-6 victory over the Arizona Cardinals.
With Mark Sanchez struggling and Tim Tebow ailing, it was McElroy who stepped off the bench in the third quarter and led the Jets downfield before throwing to Jeff Cumberland for a one-yard touchdown.
Sanchez had gone 10-of-27 for 91 yards with three interceptions before being pulled.
Greg Zuerlein booted a 54-yard field goal 26 seconds from the end of overtime as the St Louis Rams edged the San Francisco 49ers 16-13.
Zuerlein's 53-yard kick had forced overtime at the end of the fourth quarter.
The overtime kick meant the two teams narrowly avoided a second tie in three weeks.
The Denver Broncos sealed the AFC West title with a 31-23 win over the Denver Broncos.
Peyton Manning threw three touchdown balls, moving him to a franchise-record 29 for the season, and made 242 yards.
The Cleveland Browns were 20-17 winners over the Oakland Raiders, with Brandon Weeden setting a new career-high of 364 throwing yards.
Weeden also touched down to cap a stunning display that ended a 12-game losing streak away from home.
The Pittsburgh Steelers closed out a 23-20 victory over the Baltimore Ravens, with a dramatic 42-yard field goal from Shaun Suisham completing the win in the final seconds.
The Ravens could have booked their place in the play-offs with a win but instead saw a 15-match winning run at home snapped.
Elsewhere, the Cincinnati Benglas beat the San Diego Chargers 20-13 - Andy Dalton making the go-ahead score.
Tony Romo passed Troy Aikman's franchise record for touchdown passes as the Dallas Cowboys beat the Philadelphia Eagles 38-33.
The first of Romo's three touchdown passes was his 166th with the Cowboys, enough to move him past Aikman as Dallas rallied to beat the reeling Eagles, who have now lost eight straight.
Their defeat came despite 169 yards and two touchdowns from rookie running back Bryce Brown.