CARSON, Calif. (AP) — Philip Rivers' sharp throw found Antonio Gates in the middle of the end zone, and StubHub Center shook with cheers from fans who were thrilled to see this familiar teamwork in a brand-new setting.

Although the rest of this preseason opener belonged to the Seattle Seahawks, at least the Los Angeles Chargers opened their new home with a classic San Diego connection.

Rivers threw a 5-yard scoring pass to Gates on the opening drive of the Chargers' first preseason game since relocation, but the Seahawks' backups otherwise dominated a 48-17 victory Sunday night.

The Chargers had 21,054 fans in their tidy new home for the first game of a three-year residency at 27,000-seat StubHub Center. The team moved 111 miles north into a stadium built for soccer, yet providing an undeniably intimate NFL experience for fans.

"The atmosphere was great," Gates said. "I really wasn't expecting a full house. I assumed that Seattle would bring their fans, and we would have some Los Angeles fans that would be there to support us. I was more anxious to see what we were about as a team."

Rivers and his first-team offense were excellent, marching 75 yards in 13 plays capped by Gates' TD catch. Although many things are changing for the Chargers this season in LA, they've still got Rivers and Gates going into their 14th year as teammates.

"You're talking about countless hours and hard work and practicing with anticipation of certain looks," Gates said. "The balance we had that first drive, it was great to get off to the right start."

The rest of the night was more impressive for Seattle. The Chargers' revamped defense clearly has work to do under new coordinator Gus Bradley after giving up 459 yards to the Seahawks, whose reserves mostly got off to a stellar start.

"Really good first night for us in a lot of ways," Seattle coach Pete Carroll said. "It started off with the defense not getting off the field the way we like to see them do. After that, I think we played pretty good football, save one play or so."

Russell Wilson led the Seahawks to a field goal in his only drive with Seattle's first-team offense. The rest of Seattle's 34-point first half was a showcase for its backup defense, which forced three turnovers, and a solid second-team offense led by Trevone Boykin, who passed for 189 yards.

"He did beautifully," Carroll said. "Threw the ball really well. Moved well, made some plays with his feet. Just was in really good command of what was going on."

Terence Garvin returned a tipped interception 37 yards for a Seattle TD, and Chris Carson cashed in a 1-yard TD run after LA's Kellen Clemens fumbled a handoff with Andre Williams.

Clemens threw a 74-yard TD strike to speedy Travis Benjamin, but Rivers' backup also had two interceptions on deflected passes.

"We turned the ball over and put our defense in poor positions early," Anthony Lynn said after his first game as the Chargers' new coach. "I thought we started well. I didn't like it when the (second-stringers) came in. We stopped playing Charger football."

COZY CONFINES: StubHub Center appears to fulfill the Chargers' promise to provide a unique place to watch football. The smallest stadium in the NFL has exceptional sight lines and remarkable closeness to the field — and the Chargers Cannon is really loud when the home team scores.

"From a player's perspective, you want to have that home-field advantage type of feel," said LaDainian Tomlinson, the Chargers Hall of Famer and a special assistant to owner Dean Spanos. "The kind of Seattle feeling that they have, the 12th Man, trying to feel something similar for this place, I think it would be a success for everyone if that could happen."

BENNETT SITS: Defensive lineman Michael Bennett remained seated on the Seahawks' bench with a towel on his head during the national anthem. The Pro Bowler said he plans to sit all season. "I just wanted to be able to use my platform to be able to continue to speak over injustice," he said.

INJURIES

Chargers: Linebacker Denzel Perryman left the field on a cart after Los Angeles' first defensive series with a left ankle injury. The Chargers were crushed by injuries in each of the past two seasons, and Perryman is expected to call the plays as their starting middle linebacker this fall. He returned to the sideline in the second half on crutches with his foot in a walking boot. "I'm not sure how bad it is right now," Lynn said.

Seahawks: Safety Jordan Simone sprained his left knee on a kickoff return. Receiver Paul Richardson sprained his shoulder.

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