Broncos QB Peyton Manning was intercepted three times in the first quarter by the Falcons, who held on for a 27-21 victory Monday night. (AP)

After a marathon 56-minute first quarter, it seemed likely that the Falcons' Monday night game against the Broncos would last until after midnight.

No one thought the outcome would still be undecided then, not after the Falcons used four first-quarter takeaways to soar to a commanding early lead. But the Falcons relaxed on defense and tightened up on offense, allowing the Broncos (1-1) to climb back with two Willis McGahee touchdown runs.

Only when Atlanta receiver Julio Jones turned a short crossing route on third and 5 into a 6-yard gain just before the two-minute warning could the Falcons finally breathe easy in a 27-21 win at the Georgia Dome.

Michael Turner's 15-yard run two minutes later earned the Falcons (2-0) the first down they needed to keep Broncos QB Peyton Manning from getting another chance. And that was it for the three-hour, 27-minute affair that was protracted by procedural issues, instant-replay delays and deliberations between the officials that had both teams steaming at times, although Atlanta coach Mike Smith never lost his cool like former NFC South rival John Fox did on the opposite sideline.

When the game turned: If the crowd had been a late-arriving one, it would have missed a sequence that defined the game. Tight coverage from Falcons CB Dunta Robinson forced a drop on first down, DT Peria Jerry overwhelmed Denver's blocking to engulf McGahee for a 1-yard loss on second down and S William Moore intercepted Manning on third down. Atlanta scored three plays later and eventually bolted to a 20-0 lead, built as much by Broncos giveaways -- four in all -- as the Falcons' own play.

Highlight moments: On all three of their first-quarter interceptions, the Falcons masked their coverage, leaving the Broncos baffled and dazed. "(Mike) Nolan and their defense did a good job of disguising and mixing it up on us," Broncos WR Eric Decker said.

Top-shelf performances: Falcons Moore -- interception, sack, two passes defensed, eight total tackles; Falcons QB Matt Ryan -- 24-of-36 passing, 219 yards, two touchdowns, no interceptions, 101.5 rating; Falcons WR Roddy White -- eight catches for 102 yards, touchdown.

What they said about the first interception:

  • Falcons S William Moore: "I was just roaming the field, and we were in zone coverage and I looked Peyton off a little bit."
  • Falcons LB Sean Weatherspoon: "Willy Mo, always ready. He's one of those players that can impact the game and change the game; he's so athletic and he's a smart player."

What they said about Manning's three first-quarter INTs:

  • Manning: "We fought back and had a chance at the end, but I put our team in too big of a hole."

  • Broncos coach John Fox: "Remember, Peyton Manning is a new quarterback in our system. He's adjusting to teammates, adjusting to the things we're doing. It's not going to happen overnight." 

Numbers you should know: The Falcons have won 11 straight games and 34 of 36 in their history when finishing with a plus-four turnover margin.

Injury update: Falcons CB Asante Samuel left the game with a head injury but returned; CB Chris Owens left with a head injury and did not return; DE John Abraham briefly departed because of a knee injury, but returned.

Going forward: The Falcons continue their quest to be unofficial AFC West champions next Sunday at 2-0 San Diego before stepping into divisional play against Carolina seven days later. The schedule offers Atlanta a realistic chance to start 6-0 if it wins at San Diego. After the Panthers, the Falcons visit Washington before completing AFC West play against Oakland on Oct. 14. ... Next Sunday, the Broncos host the Texans (2-0), whose defense is No. 1 in the NFL in points allowed, although their first two opponents were the Dolphins and the Jags. After a home game against the Raiders the following weekend, Denver travels to New England to play the Patriots.

For up-to-the-minute Broncos updates, follow Andrew Mason on Twitter @CBSSportsNFLDEN and @MaseDenver.