Matt Ryan and the Atlanta Falcons kept pace with the 10-1 Houston Texans after a scrappy 24-23 win at the Tampa Bay Buccaneers on Sunday.
The Cleveland Browns took advantage of the Pittsburgh Steelers' injury problems to record a 20-14 win over their old rivals while Peyton Manning threw for 285 yards and two touchdowns as his Denver Broncos beat Kansas City 17-9.
The Cincinnati Bengals pushed themselves into playoff contention with a 34-10 crushing of the Oakland Raiders and Jay Cutler enjoyed a winning return with Chicago against the Minnesota Vikings.
Ryan threw for 353 yards and a touchdown, with one interception, while receiver Julio Jones had 147 yards and a touchdown, but the Falcons had to work for their win against an improved Tampa Bay (6-5).
The Buccaneers grabbed the lead in the fourth quarter when Doug Martin ran his second touchdown of the game, a one-yard rush at the end of an 82-yard drive.
Connor Barth's 48-yard field goal extended the lead to 23-17 but Falcons running back Michael Turner powered in for a three- yard touchdown to give Atlanta a one-point advantage.
Still, the Bucs had one more chance to secure a win but this time Barth failed with a field-goal attempt from 56 yards as Atlanta held on against their divisional rivals.
The Steelers were without starting quarterback Ben Roethlisberger and his deputy Byron Leftwich through injury and 37-year-old third-choice Charlie Batch struggled, throwing three interceptions in the loss at Cleveland.
A 15-yard rushing touchdown by Trent Richardson proved to be the game-winner for a Browns team that took full advantage of eight turnovers by Pittsburgh, including a costly late fumble by running back Chris Rainey.
It was just the second time in 18 games that Cleveland (3-8)has enjoyed victory over the Steelers (6-5) and the win damages Pittsburgh's hopes of catching the Baltimore Ravens in the AFC North.
After the Chiefs took the lead with two field goals, Manning led the Broncos (8-3) to their sixth straight win with touchdown passes to tight end Jacob Tamme and wide receiver Demaryius Thomas.
Cincinnati continue to quietly improve with quarterback Andy Dalton throwing for three touchdowns and 210 yards against struggling Oakland to move the Bengals to 6-5 after their third win in a row.
Quarterback Cutler was back with the Bears after missing last week's loss to San Francisco with a concussion and he threw for 188 yards and a touchdown in an important 28-10 win over the Vikings.
The Indianapolis Colts improved to 7-4 with a 20-13 victory over the Buffalo Bills but the Seattle Seahawks suffered a surprise 24-21 loss at the Miami Dolphins.
(Reporting By Simon Evans)