Published: Sep 30, 2012 9:54 PM EDT
Updated: Oct 01, 2012 6:32 AM EDT

DENVER (AP) - Peyton Manning ruined Dennis Allen's homecoming Sunday when the Denver Broncos handed the Oakland Raiders their worst loss in this heated AFC West rivalry in a half-century.

Manning picked apart a secondary filled with backups, then walked off the field with a clean jersey and a smile a mile wide as the Broncos bounced back from back-to-back close losses with a resounding 37-6 rout of their archrival.

"Well, it was nothing more than an old-fashioned butt-whupping," quarterback Carson Palmer said after the Raiders' first loss in Denver in five seasons and their worst defeat in the series since Oct. 5, 1962, when they were humiliated 44-7 at old Bears Stadium.

Manning had his record-extending 65th 300-yard passing game, wasn't sacked, intercepted or hurried and threw three touchdown passes while controlling the clock and watching Willis McGahee record his 32nd 100-yard rushing game, tops among active NFL players.

"They outcoached us, they outplayed us, they beat us in every phase of the game," said Allen, Oakland's first-year coach who was Denver's defensive coordinator in 2011. "So, there's not a lot positive that you can take from it."

Allen pledged to use the upcoming bye week to evaluate everything from schemes to personnel.

"We've got to come up with a way to play better," he said.

Oakland was without its two best cornerbacks in Ron Bartell (shoulder) and Shawntae Spencer (foot), so Pat Lee started at left cornerback and Michael Huff moved over to right cornerback with Matt Giordano sliding into his spot at free safety.

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.

It proved too tough for the Raiders to face the four-time MVP without their top two cornerbacks.

"Well, it's hard to play against Peyton Manning no matter what," Allen said. "But we've got the guys that we have, and that's who we've got to go out and play with and we've got to play at an NFL level. And so we're not going to use injuries as a crutch."

The Broncos (2-2) gained 101 more yards than the Raiders (1-3) in the first half, but only led 10-6 going into the locker room, thanks to two big blunders: a Demaryius Thomas fumble after a 40-yard reception and kicker Matt Prater's misfire on a pass to left guard Zane Beadles on a fake field goal.

"Maybe give Manning-Stokley a chance before Prater-Beadles," Manning joked.

Thanks to those gaffes, the Raiders came out of the tunnel for the second half feeling fine.

"We were in good shape at halftime," said Lamarr Houston, who recovered Thomas' fumble. "We were in the game."

Not for long.

The Raiders were outscored 27-0 after the break, and the Broncos even didn't punt all afternoon - only the fifth time that's happened in franchise history.

"Nothing magic I could share with you," Manning said, when asked about Denver's quick start to the second half.

The Raiders gave up three TDs in the third quarter while going three-and-out three times. They failed to cover wide receiver Eric Decker on his 17-yard touchdown catch and nobody covered running back Lance Ball on his 14-yard scoring reception.

In between, McGahee rumbled in from 2 yards after David Bruton got a hand on Shane Lechler's 2-yard punt at the Oakland 18.

Oakland's troubles after halftime continued a disturbing trend. The Raiders have been outscored 55-7 in the third quarter so far.

"Well, I'm not exactly sure what that is, but we need to get it figured out because we haven't played good in the third quarter," Allen said. "The time of possession is killing us."

The Raiders had the ball less than 23 minutes.

The area that's most disconcerting? That's easy, Allen said.

"Third down. Both sides of the ball. Not good enough."

Oakland was 1 for 12 on third downs, Denver 10 of 16.

"You've got to stay on the field and we didn't do that," Palmer said. "We left our defense hanging, we left them on the field too long in the third quarter."

The Raiders' best chance at beating Denver was Darren McFadden, their leading rusher and receiver who has made a career of beating up the Broncos. But he gained just 34 yards on 13, averaging just 1.9 yards a carry after Oakland's opening drive.

"I just feel we never really stayed in sync on offense," McFadden said.

Manning was sacked eight times in his first three games in Denver, but the Raiders couldn't get to him before or after center J.D. Walton hurt his left ankle and was replaced by veteran Dan Koppen in the second quarter.

"That's obviously an area we've got to improve in," Allen said. "We've got to get to the quarterback. We've got to look at what we can do to generate a pass rush, but pass defense works collectively. It's pass rush and pass coverage together."

Both were absent Sunday.

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