OAKLAND (AP) — After enduring one of the toughest weeks of his life and career, Raiders coach Dennis Allen's return to the Oakland Coliseum ended with another painful memory.

Just the way most games have this season.

Carson Palmer threw an interception that thwarted a scoring chance and fumbled near his own goal line to send the Raiders to a sixth straight loss, 26-13 against the Denver Broncos on Thursday night.

The Raiders (3-10) played the game with heavy hearts after Allen's father, Grady, died earlier in the week from cardiac arrest. Allen was in the Dallas area for two days but came back to the Bay Area on Wednesday to coach the game.

About the only bright spot for the first-year Raiders coach is that the team's longest skid since losing six in a row in 2007 is hardly the worst thing to happen to him this week.

"I took my father off life support, and that's not easy to do," Allen said, his voice cracking. "So was it hard? Yeah, it was hard. But I know my father would want me to be here with this football team, and I wanted to be here with this football team. So I'm sure you guys can imagine it wasn't an easy situation."

Allen said he was overwhelmed by support from players, assistants and those throughout the NFL. His players had talked during the short week about rallying around their coach, too.

Instead, they came out flat against a fierce AFC West rival, were swept in the season series by the Broncos for the first time since 2006 and added to the mounting pressure on Allen's job.

Peyton Manning threw for 310 yards and had his 30th touchdown pass of the season on the game's opening drive to help Denver roll to its eighth straight victory. Knowshon Moreno ran for 119 yards and a score on a career-high 32 carries, and Matt Prater kicked four field goals.

The Broncos (10-3) moved a half-game ahead of New England and Baltimore for the second-best record in the AFC. Denver visits Baltimore next week in a game that will help decide who gets a first-round playoff bye.

"I felt like we got decent pressure on him at some times," Raiders linebacker Philip Wheeler said. "I feel like we just got to get off the field on third downs, man. We can't have those long drives."

The game was mildly competitive for only a brief time as Oakland scored late in the first half on a touchdown pass from Palmer to Darren McFadden and then started with the ball in the third quarter down 13-7.

McFadden, returning from a four-game absence for a sprained right ankle, left late in the fourth quarter with another setback to the injury. That put the damper on a solid comeback performance, breaking off a 36-yard run on the first play from scrimmage, but the drive stalled in Denver territory after that and the Broncos took the game over.

"Extremely frustrating," Palmer said. "To rack up this many losses in a row in the fashion that we've done is just extremely frustrating."

Manning, who joined Brett Favre as the only quarterbacks in NFL history with 5,000 career completions, converted a third-and-11 with a perfectly placed 22-yard pass to Demaryius Thomas. Manning followed that with a 29-yard completion to Eric Decker, but the drive stalled after a pass-interference call on Matt Giordano gave the Broncos a first down at the 1. Prater's 20-yard field goal made it 16-7.

Mike Goodson then made the ill-advised decision to return a kick from 8 yards deep in the end zone, forcing Oakland to start a drive at the 8. Von Miller then beat Khalif Barnes for a sack on third down, stripping the ball from Palmer. Mitch Unrein recovered at the 2 and Moreno scored two plays later to make it 23-7.

"The guy got a good pass rush. And being in that situation backed up like that, I've got to throw the ball out of bounds," Palmer said. "I didn't have the guy I wanted to throw the ball to open, tried to pull the ball back and throw it to another guy. Obviously, looking back now, I wish I would've just chucked the ball out of bounds."

Prater added another field goal later in the third quarter and Manning went on to his record 12th season with 10 wins as a starting quarterback.

The only remaining drama was whether quarterback project Terrelle Pryor would get his first action of the season for Oakland. He didn't, giving the frustrated Raiders fans yet another reason to be upset even though Palmer added a 56-yard TD pass to Darrius Heyward-Bey and finished with 273 yards passing.

The Raiders won the coin toss but decided to defer until the second half. The decision backfired as Manning converted three third downs on a 68-yard drive that was capped by a 6-yard pass to Joel Dreessen that was Manning's 30th touchdown pass of the season.

Prater added two field goals after Broncos' drives stalled inside the Oakland 20 as Denver extended the lead to 13-0. The momentum shifted after Phillip Adams' intercepted an underthrown pass from Manning to Matthew Willis in the end zone.

Oakland responded with an 80-yard drive capped by a 6-yard screen pass to McFadden.

"This year, our consistency is not where it needs to be," Allen said. "There's times where we do some really good things, but there are other times where we compound mistakes at times. That's where we've got to do a better job."

After the game police said a man fell from the upper deck at the stadium shortly before kickoff and was in serious condition at a hospital. Initial reports called the fall an accident, but police said it remained under investigation. The team had no comment.