SAN DIEGO -- Those predicting the Denver Broncos' demise when Peyton Manning got hurt are having second thoughts.

Brock Osweiler improved to 3-0 and Denver breezed past the San Diego Chargers 17-3 on Sunday at Qualcomm Stadium.

With the win, the 10-2 Broncos tightened their grip on first place in the AFC West and kept pace with the AFC-leading Cincinnati Bengals in the conference in the race for home-field advantage in the postseason.

With New England losing to Philadelphia, the Broncos are the conference's No. 2 seed.

What's been uprooted is the notion the Broncos would collapse without Manning, the five-time NFL MVP.

"No one blinked with this being a road game," Osweiler said. "We got a quick start, a quick score and then we slowed down a bit throughout the game. We did what we had to do to stay into it."

Osweiler completed 16 of 26 passes for a touchdown and 166 yards. He was intercepted once.

"I think he continues to grow," Denver coach Gary Kubiak. "The thing I really liked about him was he learns from his mistakes."

The Broncos raced to a 17-0 second-quarter lead and coasted in for the win.

For the dreadful Chargers (3-9), the loss was their fifth straight home defeat and fifth in a row against the AFC West.

"Obviously not too many bright spots," said Chargers coach Mike McCoy said.

Quarterback Philip Rivers was 18 of 35 for 202 yards. He had an interception returned for a touchdown and San Diego turned it over three times.

In addition to Rivers' interception, running back Melvin Gordon and wide receiver Malcom Floyd fumbled in the team's first two second-half possessions. Gordon, a rookie, was benched after another fumble went out of bounds, the latest stumble in a frustrating season for the first-round pick.

"You're not going to play if you put the ball on the ground," McCoy said.

Added Gordon: "You start getting into a rhythm or a groove and then you have a bad play and it can just kill the whole vibe."

Rivers was sacked four times and the Chargers failed to score a touchdown for the second game in a row.

"It's kind of sad not being there for him because he is so good," Floyd said.

The constant is the Broncos' top-ranked defense.

"They've got a lot of guys who can rush," a resigned Rivers said. "At times we moved the ball and got into their territory. We couldn't finish drives and then we had the turnovers. That's a heck of a group and we didn't rise to the challenge."

Late in the first half, Josh Lambo's 51-yard field goal sliced the Chargers' deficit to 17-3. Lambo was wide right on a 48-yard attempt earlier in the second quarter.

Denver's Brandon McManus was true on his 23-yard attempt, stretching the Broncos' advantage to 17-0

The Broncos increased their lead to 14-0 in the first-quarter's waning seconds.

Rivers, under duress, delivered his pass early and linebacker Danny Trevathan broke to the ball. He brought it back 25 yards for a touchdown, the fifth pick-6 Rivers has thrown this season and the fifth defensive touchdown on the season for Denver.

"It was not a good throw," Rivers said. "It was a bad play all the way the around."

Osweiler's 3-yard touchdown pass to wide receiver Demaryius Thomas capped a 76-yard opening drive.

"The main thing was to start fast," Thomas said.

Thomas finished with a game-high 61 yards on six receptions. Each catch was greeted with a roar, as Broncos fans filled Qualcomm Stadium.

"We've gotten used to it, unfortunately," a resigned Rivers said.

Not Osweiler.

"Oh my god, it was unbelievable how much orange," he said. "It's just a testament that we truly have the best fans in the world."

Those cheering the Chargers have seen them lose five of their past seven games against AFC West foes. Although the number of losses overall is what disappoints Rivers.

"When you have nine of them, they all hurt at this point because there have been so many," he said.

NOTES: Chargers LT King Dunlap (ankle) and RG D.J. Fluker (concussion) didn't start. ... WR Dontrelle Inman was carted off the field in the first quarter after absorbing a helmet-to-helmet hit from S David Bruton Jr. ... CB Brandon Flower exited with a first-quarter knee injury. ... GM Tom Telesco signed a contract extension. ... Broncos OLB DeMarcus Ware (back) and S T.J. Ward (ankle) were inactive. ... Broncos ILB Danny Trevathan left the game with a concussion.