DENVER >> Now that they’re teammates, Peyton Manning can celebrate when Tracy Porter returns an interception for a touchdown.

Three seasons ago Porter denied Manning a second Super Bowl title when he returned an interception 74 yards to seal the New Orleans Saints’ win over the Indianapolis Colts.

Their Denver debut Sunday night was a success thanks to Manning’s magnificent return from a year’s absence and Porter’s 43-yard interception return for a score that sealed their 31-19 win over the Pittsburgh Steelers.

The Broncos’ final drive stalled at the Steelers 8 and Matt Prater’s short field goal left Roethlisberger with 3 minutes to erase a 25-19 deficit.

“We wanted to get a touchdown there at the end and it was frustrating to have to settle for a field goal,” Manning said. “Hate to give Roethlisberger a chance in the two-minute drill.”

Roethlisberger had gone a great job matching Manning’s mastery of the no-huddle and keeping the four-time MVP on the sideline much of the night by converting 11 of 19 third downs.

After a 19-yard completion to his 39, Roethlisberger threw an incomplete pass, then tried to thread a pass to receiver Emmanuel Sanders along the left sideline.

Porter, who also had eight tackles and broke up five passes — the most by a Denver defender in 11 seasons — stepped in front and took it to the house.

“There’s a safety over the top so I’m aggressive on anything short,” Porter said. “The quarterback tried to fit it in there and I just made a play on the ball. Any defensive back playing opposite Champ (Bailey) is going to get the work. I just made the most of my opportunity.”

“I should’ve called timeout,” Roethlisberger said. “The play clock was running down, I hate to burn timeouts. I should’ve. We were kind of all over the place.

“There’s no one to blame but myself. I already told my teammates and coaches that it’s my fault. It’s on me. It’s disappointing. I hate to let my team down, my coaches, the fans. That loss is squarely on my shoulders. I’ll take that and get better and learn from it.”

After 1 year, 8 months and 2 days away from the game, Manning couldn’t wait to resume his career, but Roethlisberger was determined to keep him on the sideline, giving the Steelers more than a 10-minute advantage in time of possession.

Whenever he was between the lines, Manning was masterful, finishing with a 129.2 passer rating.

The four-time MVP coming off four neck surgeries that wiped out his final season in Indianapolis last year completed 19 of 26 passes for 253 yards and two touchdowns. He was sacked twice and bounced up both times without trouble.

Manning, jettisoned by the Colts in March after missing all of last season with a nerve injury that weakened his throwing arm, took just two snaps in the third quarter. But one was a 71-yard touchdown throw to Demaryius Thomas, Manning’s first as a Bronco and the 400th of his career.

He reached the milestone in his 208th career game. Dan Marino did it in his 227th game and Brett Favre in his 228th.