Oct 25, 2015; San Diego, CA, USA; San Diego Chargers quarterback Philip Rivers (17) and offensive coordinator Frank Reich talk during a stoppage in play during the second half of the game against the Oakland Raiders at Qualcomm Stadium. Oakland won 37-29.

Orlando Ramirez USA TODAY Sports

SAN DIEGO (AP) -- Philip Rivers was called for intentional grounding, ripped his helmet off as he walked to the sideline and tossed it at the bench.

That pretty much summed up how Sunday went for the Chargers, who were embarrassed for three quarters by the Oakland Raiders before scoring three times in the fourth quarter of a 37-29 loss to their rivals and possible future stadium mates.

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"It was sickening in how fast it happened," said Rivers, who had thrown two interceptions long before he threw three touchdowns passes. "Shoot, it was 30-6 at halftime."

Said coach Mike McCoy: "Nothing good happened after the first play. It was poor all around. It's pathetic. That first half was pathetic. No excuses it starts with me. Put it on me."

Derek Carr threw three touchdown passes, including a nifty 52-yarder to Amari Cooper, and Oakland turned two interceptions of Rivers into 10 points in what could be the last showdown between the AFC West foes played in San Diego.

It was the first meeting of the Raiders (3-3) and Chargers (2-5) since their owners announced plans to build a $1.7 billion stadium in an industrial Los Angeles suburb if they can't get new stadiums in their home markets.

Coming off a bye, the Raiders looked quicker and more efficient. They scored on their first seven drives and kept the Chargers out of the end zone until the fourth quarter.

Cooper, the first-round draft pick out of Alabama, caught a short pass from Carr on an inside screen and raced through the defense to give the Raiders a 30-3 lead just before halftime. He finished with five catches for 133 yards.

Carr, the second-year pro out of Fresno State, also threw touchdown passes of 23 yards to Clive Walford and 25 yards to Michael Crabtree. Carr was 24 of 31 for 289 yards.

The Raiders didn't have to punt until midway through the third quarter.

"That's the longest we have sustained really good football as a team in all three phases," first-year coach Jack Del Rio said. "I'm really happy for our guys."

The Chargers got in trouble right away in their third consecutive loss.

Oakland's Malcolm Smith intercepted a tipped pass on the game's third play and returned to the San Diego 2. Latavius Murray scored on a 1-yard run two plays later.

Sebastian Janikowski kicked the first of his three field goals, from 29 yards, and Carr found Walford for an easy 23-yard score and a 17-3 lead early in the second quarter.

Two plays into the next San Diego drive, Rivers tried to force a pass to Keenan Allen and it was picked off by DJ Hayden, giving the Raiders the ball at the Chargers 31. Janikowski kicked a 32-yard field goal.

The Chargers played without star tight end Antonio Gates (knee) and safety Eric Weddle (groin), and rookie running back Melvin Gordon was benched for the first half, apparently more punishment for his two fumbles in a gut-wrenching 27-20 loss at Green Bay. Gordon was benched for the second half of that game after losing one of the two fumbles. He has lost three of four fumbles this season.

"I hate watching," said Gordon, who is still looking for his first NFL touchdown. "It don't sit well with me watching my teammates trying to go out there and make plays and I'm on the sideline looking helpless when I know I can help change things out there."

The Chargers' future in San Diego is uncertain. They walked away from negotiations with city and county officials for a new stadium in mid-June and have been focusing on getting to Los Angeles. The Chargers and Raiders apparently were spooked into action after St. Louis owner Stan Kroenke announced plans for a stadium in Inglewood.

Rivers, who threw for a career-high 503 yards a week earlier in Green Bay, was 38 of 58 for 336 yards. He had scoring passes of 31 yards to Ladarius Green and 8 and 6 yards to Danny Woodhead, all in the fourth quarter.

"We weren't in sync offensively," Rivers said. "We didn't execute early and I think defensively would say the same thing. It wasn't a lack of want-to or effort. Shoot, we just didn't play very well."