San Diego's defense got the best of Kurt Warner and Arizona's first-team offense Saturday night.
The Cardinals starters managed just a field goal, set up by a game-opening 89-yard kickoff return by diminutive rookie LaRod Stephens-Howling, in San Diego's 17-6 victory.
Stephens-Howling, a 5-foot-7 seventh-round pick out of Pittsburgh, also had a 63-yard kickoff return.
Warner completed 6 of 13 for 80 yards in Arizona's first home game since its Super Bowl appearance. He was intercepted by Antonio Cromartie, who stepped in front of Larry Fitzgerald for one of two picks the Chargers had in their own end zone to thwart Cardinals scoring threats.
"I just read the quarterback's eyes," Cromartie said. "He stared Fitzgerald down the whole time so I just jumped the route."
Philip Rivers was 5-for-7 for 116 yards in a little more than 1 1/2 quarters for San Diego but was sacked four times. He left after directing the team to its first touchdown.
LaDainian Tomlinson gained 18 yards in eight attempts and caught two passes for another 18.
Brian St. Pierre, given a chance by Arizona coach Ken Whisenhunt to compete with Matt Leinart for the No. 2 quarterback job, replaced Warner and was 6-for-15 for 79 yards and an interception.
Leinart came in with 8:36 to play after the Cardinals stopped San Diego on the Arizona 1-yard line. He drove the team to the Chargers 11 but his fourth-and-three pass was incomplete.
Nate Kaeding kicked a 56-yard field goal for San Diego, a yard shy of his longest, a 57-yarder at Tampa Bay last season.
San Diego improved to 1-1 in the preseason, Arizona is 0-2.
"I didn't like some of the kickoff coverage stuff. We've got work to do there," Chargers coach Norv Turner said. "It's very unlike us in the pass protection to give up that many pressures or sacks. I'm disappointed in that part. We didn't play like we're capable of playing there."
One bright spot for the Cardinals' first-team offense was the running game, worst in the NFL last season. Tim Hightower carried nine times for 42 yards. Running back Beanie Wells, Arizona's first-round draft pick, suited up but did not play. He has missed both preseason games after spraining his right ankle in his first practice.
Stephens-Howling, a backup running back at Pitt, burst through to the San Diego 7-yard line with the opening kickoff. Warner threw five yards to Hightower to the 2, but Quentin Jammer broke up a pass intended for Anquan Boldin in the end zone and the Cardinals settled for Neil Rackers' 20-yard field goal.
Later in the first quarter, Arizona drove from its 20 to the Chargers 13, but on second-and-eight Cromartie picked off Warner's pass.
"It is disappointing because we had some opportunities we didn't capitalize on like we wanted to," Warner said, "but there is going to be a lot of stuff we can learn from tonight. We will get better and be all right in a couple of weeks."
Rivers threw a 49-yard pass to Legedu Naanee on San Diego's first play, but the threat ended with consecutive sacks by Darnell Dockett and Karlos Dansby.
Rivers' short pass to Darren Sproles turned in to a 36-yard gain to set up San Diego's first touchdown. Rookie Greg Toler was called for unnecessary roughness for running in to Sproles as he stepped out of bounds. That moved the ball to the Arizona 4, where Michael Bennett bounced outside for the score.
San Diego's reserves went 95 yards in 12 plays for a score late in the half, Billy Volek throwing 11 yards to Naanee for the touchdown to make it 14-3 40 seconds before the break. Volek was 6-for-7 for 66 yards.
NOTES: Fitzgerald did not catch a pass. ... The Chargers were without three players listed as starters _ wide receiver Vincent Jackson (sprained finger), defensive end Jacques Cesaire (calf) and safety Steve Gregory (ribs). ... Arizona's No. 3 wide receiver Steve Breaston, usually the kickoff and punt returner, was out with an injured knee.