Post-game analysis: Broncos 31, Steelers 19

In a duel of attrition that saw both quarterbacks take turns exhausting the opposing defenses, one defender, who spent the night chasing wide receivers, had enough in reserve to deliver the knockout blow.

Tracy Porter's interception and 43-yard return for a touchdown with 1:58 remaining gave the Denver Broncos (1-0) a 31-19 win over the Pittsburgh Steelers at Sports Authority Field at Mile High in Denver. It also exposed the flaw of the Steelers offense, which had become one-dimensional under the weight of injuries along its offensive line and to running backs Rashard Mendenhall and Isaac Redman.

The Steelers (0-1) still managed to control the pace of the second and third quarters, and at one point ran 41 of 44 plays during a 21-minute, five-second stretch from the second to the fourth quarters. But Denver was able to stay afloat because one of those three snaps was a 71-yard Peyton Manning-to-Demaryius Thomas touchdown.

By the time Manning got the football again in the fourth quarter, he turned the tables, exhausting the Steelers with 12- and 10-play drives. Between those series, the resuscitated Broncos defense forced a three-and-out.

When the game turned: Even after the Broncos had re-taken the lead on a 1-yard Manning-to-Jacob Tamme pass 9:23 into the fourth quarter, Denver's defense still had to marshal enough energy to reverse a run in which it had allowed 17 points over Pittsburgh's last three possessions. It did, after forcing a pair of incompletions on second and 3 and third and 3, allowing the Broncos a chance to reclaim momentum and give its defense a respite for its final, late-game attack on Roethlisberger.

Highlight moments: The 71-yard Manning-to-Thomas touchdown connection with 5:41 left in the second quarter might merely have been a nice, 30-yard gain if left guard Zane Beadles had not burst out and blocked Ryan Mundy -- although, it must be noted, Beadles grabbed Mundy's jersey and wasn't called for holding.

Porter's interception provided the final margin; he was locked in man-to-man coverage on Emmanuel Sanders, but read Roethlisberger perfectly, releasing Sanders and jumping the pass, effectively ending the game.

Top-shelf performances: Manning: 19 of 25, 253 yards, 2 touchdowns, no interceptions.

Steelers LB Larry Foote: 8 tackles, one sack, one tackle for loss and a pass defensed.

Broncos LB Von Miller: Two sacks, four tackles for losses.

What they said about Porter's pick-six:

    Broncos CB Tracy Porter -- "I didn't securely catch it, but I made the play."

    Broncos CB Champ Bailey -- “He was so frustrated when that guy (Mike Wallace) caught the ball in the end zone earlier. I just told him, 'Calm down; things will bounce your way, and you'll make a play,' because he's a great player. I expect that from him every play.

    Steelers QB Ben Roethlisberger -- "I should have called timeout. The play clock was running down. I hate to burn timeouts, but I should have. We were covered all over the place."

Numbers you should know:

In the third quarter, the Broncos held the ball for only 36 seconds, but outscored the Steelers 7-3.

During a three-possession stretch from the second to fourth quarters, the Steelers converted eight of 10 third downs -- and followed one of the two failures with a 2-yard Roethlisberger run on fourth and 1.

Denver's players and coaches spoke of finding balance in the offense, and achieved it Sunday, calling 28 passes and 27 runs.

Injury update: Denver DT Ty Warren left in the second quarter with a sprained elbow that will be further evaluated Monday. Steelers OLs Marcus Gilbert and Ramon Foster left with an eye injury and a hyper-extended knee, respectively. Gilbert was being evaluated after the game, Steelers coach Mike Tomlin said.

Going forward: If there was ever a must-win game in Week 1, this was it. Denver's next four games are daunting, with trips to Atlanta and New England sandwiching a homestand against the Texans and Raiders. An 0-3 start was a legitimate possibility if the Broncos had not rallied in the fourth quarter, and with few breathers on the AFC's toughest slate, the Broncos would have been hard-pressed to dig out from that hole.

Above all else, the Steelers need better health. Without Foster and Gilbert and with Redman hurting and Mendenhall out, the Steelers couldn't marshal a consistent run game to take the pressure off Roethlisberger, and the Broncos were able to use nickel and dime packages almost exclusively in the second half. If they can get Mendenhall and LB James Harrison back next week, they can ensure that Sunday was an unpleasant blip, and nothing more.