SAN FRANCISCO (AP) – The San Diego Chargers’ vaunted defense finally got a challenge. Philip Rivers and LaDainian Tomlinson couldn’t say the same.

Tomlinson set a franchise scoring record with a career-best four touchdowns rushing, and Rivers passed for a career-high 334 yards and two more scores in the Chargers’ 48-19 victory over the San Francisco 49ers on Sunday.

Antonio Gates and Vincent Jackson caught scoring passes from Rivers, who was practically perfect as the Chargers rolled to their first 4-1 start since 2002. Rivers went 29-of-39 with a poise beyond his five career starts, easily picking apart an injury-riddled secondary on a defense that already has allowed 194 points this season.

Tomlinson rushed for just 71 yards, but surpassed Lance Alworth’s Chargers record with his 84th career touchdown in the first quarter. He added three more on similarly short runs, each punctuated with a ball flip and a wave.

The three-time Pro Bowl running back scored four TDs on three runs and a reception against the Jets last season, but had never rushed for four scores in a game.

San Diego scored 35 first-half points against the 49ers (2-4) before finishing the club’s highest-scoring performance since 1986, matching a 48-point game against Buffalo last season.

Coach Marty Schottenheimer didn’t play it safe for a change, either: Rivers and Tomlinson stayed in the game with a 22-point lead in the final minutes, finally adding L.T.’s last TD with 4:20 to play.

And San Diego seemed to need plenty of points for a change: In the 49ers’ fourth home game in five weeks, Alex Smith kept one of the NFL’s top defenses on its heels with a strong first half before fading late.

Bryan Gilmore and fullback Moran Norris caught scoring passes as the Chargers gave up more points in the first half alone than they allowed in any of their first four games. But San Diego shut out San Francisco in the second half, with Smith finishing 20-of-31 for 214 yards.

Gates turned a short catch into a 57-yard score on the Chargers’ opening possession when three Niners missed tackles, but San Francisco responded with a 74-yard drive capped by Smith’s needle-threading TD throw to Gilmore.

San Diego had a 91-yard scoring drive later in the first quarter capped by Tomlinson’s first TD, and Jackson blew past third-string cornerback Marcus Hudson for a 33-yard TD catch early in the second.

Two pass-interference calls set up Tomlinson’s second TD run, putting San Diego up 28-10 with 36 minutes still to play – yet the Niners made another impressive drive, using a trick play before Norris’ 2-yard TD catch.

Rivers was 14-of-15 with a perfect passer rating shortly before Ronald Fields sacked him in the end zone for a safety 3:12 before halftime. But Smith’s next pass was tipped and intercepted by Luis Castillo, and Tomlinson hurdled high over the goal line for his third score with 33 seconds left.

San Diego’s 35 points were the second-most ever allowed by a San Francisco defense in one half. Rivers passed for 235 yards in the first half – 7 fewer than his total last week against Pittsburgh.

AP-ES-10-15-06 1936EDT