DENVER -- Instead of coming from behind, Peyton Manning spent the second half piling it on.
Off to a fast start for the first time as a Bronco, Manning led Denver to three third-quarter touchdowns Sunday in a stress-free, 37-6 rout over the Oakland Raiders -- the first time Denver has beaten its AFC West rival at home since 2007.
Denver (2-2) outscored the Raiders 27-0 in the second half.
Picking and poking with short crossing routes and screen passes against a depleted Oakland defense, Manning finished with 338 yards and three scores. For the second straight game, he didn't throw an interception. Last week, he set a career high with 26 incompletions. This week, he threw eight, with 30 completions.
Willis McGahee finished with 112 yards rushing for the Broncos for his 32nd career 100-yard game, the most of any active player.
Manning led the Broncos to their first opening-quarter touchdown of the season -- an 11-play, 80-yard drive on the game's first possession that included drive-sustaining completions on third-and-6 and fourth-and-1. He capped it with a 22-yard touchdown pass -- zipped through triple coverage to Joel Dreessen, who laid out for the catch.
Shortly after that, Manning answered a lot of questions about his arm strength, rolling to his right, stopping on a dime, leaving his feet and throwing across his body for a 23-yard completion to Demaryius Thomas. That set up a field goal and a 10-3 lead. The Broncos gained 101 more yards than the Raiders in the first half, but led 10-6 going into the locker room.
The game never felt that close and soon after the teams returned, it wasn't anymore.
Manning drove the Broncos 79 and 62 yards for touchdowns, capping one drive off with a short pass that Eric Decker took in for a 17-yard touchdown and the other with a similar 14-yard connection with Lance Ball.
In between, David Bruton got his hand on a Shane Lechler punt to give the Broncos the ball at the Oakland 18. McGahee capped that four-play drive with a 2-yard score up the middle.
By the time the third quarter was over, the Broncos led 31-6. Their 21 points were 14 more than they'd scored in the third quarters of their first three games combined.
Oakland, meanwhile, has now been outscored 55-7 in the third quarter. Under new coach Dennis Allen -- Denver's defensive coordinator last year -- the Raiders have allowed more points over the first four games (125) than in any year except 1961 and 1962, before the late Al Davis took over.
Carson Palmer finished 19 for 34 for 202 yards for the Raiders (1-3) and the Broncos, who had allowed Darren McFadden 508 yards and three touchdowns over the last four meetings, held him to 34 yards on 13 carries.
Oakland came in without injured starting cornerback Shawntae Spencer, which forced the Raiders to move a natural safety, Michael Huff, over to the corner and bring in backup Matt Giordano to take his place.
All of which made the league's 23rd-ranked defense coming in that much more vulnerable. Manning, who padded his record total of 300-yard passing games to 65, looked like the Manning of old, standing at the line, diagnosing a defense, then choosing, in most cases, to throw quick screens or crossing routes, which his receivers turned into big gains.
Thomas finished with five catches for 103 yards, Decker had seven catches for 79 and McGahee caught six balls out of the backfield for 23 yards.
The referees were no factor in this game. They called nine penalties, five for 41 yards against the newly disciplined Raiders, who came into the game near the bottom of the league in that category and will stay there.
The Broncos, meanwhile, had amassed more than $150,000 in fines over the first three weeks and, though there weren't any obviously finable infractions in this one, they played like bullies, outgaining the Raiders 503-237. Oakland didn't get its first first down of the second half until the 12:45 mark of the fourth quarter.