Manning came off the bench and piloted four Denver scoring drives in a 27-20 win over San Diego.
The victory, after reigning Super Bowl champion New England Patriots fell 20-10 to the Miami Dolphins on the final day of the regular season, lifted the Broncos to the American Football Conference West division title and top seed.
Manning, who missed seven weeks with a foot injury and was in uniform as backup to Brock Osweiler, received a thunderous ovation when he took over from the ineffective starter in the third quarter.
He promptly launched an 80-yard, eight-play drive capped by CJ Anderson’s one-yard touchdown run that gave Denver a 14-13 lead.
Broncos coach Gary Kubiak said he decided to go with the 39-year-old Manning after the Broncos coughed up their fifth turnover of the game — even though the errors weren’t all on Osweiler’s head.
“Just my gut told me to turn it over to him,” Kubiak said. “I’m just very proud of him. He’s worked really hard to stay there for us and it couldn’t be a bigger day to be there for us.”
Broncos cornerback Aqib Talib said Manning’s entry into the contest “lifted the whole stadium”.
A defeat would have cost the Broncos a first-round bye, but now they’ll have a week to regroup — as will the Patriots.
The bye will be welcome for New England, whose superstar quarterback Tom Brady absorbed some hard hits as he completed just 12 of 21 passes for a season-low 134 yards and no touchdowns.
“We didn’t do enough things well enough to win,” coach Bill Belichick said after the Patriots offense was held to 196 total yards. “That was a problem across the board.”
The Pittsburgh Steelers snatched an AFC wildcard berth with a 28-12 victory over the Cleveland Browns, coupled with the New York Jets’ 22-17 loss to the Buffalo Bills. The Jets controlled their own destiny, needing only a win to advance, but ex-coach Rex Ryan and the Bills played spoiler.
The Houston Texans trounced the Jacksonville Jaguars 30-6 and won the AFC South division title for the first time since 2012. The Texans face a tough wildcard challenge against the Kansas City Chiefs, who are charging into the post-season on a 10-game winning streak after a 23-17 victory over the Oakland Raiders.
The Steelers’ first round foes will be the Cincinnati Bengals, who beat Baltimore 24-16 to complete the third 12-win season in club history.
The Carolina Panthers finally locked up the top seed and home field advantage in the NFC with a 38-10 victory over the Tampa Bay Buccaneers. Quarterback Cam Newton ran for two touchdowns and passed for two more as the Panthers bounced back from their only defeat of the season last week.
The Arizona Cardinals own the other NFC bye as the number two seeds, but they got a reality-check from the Seattle Seahawks who cooled off the red-hot Cardinals 36-6.