SAN DIEGO (AP) — Vincent Jackson reminded the San Diego Chargers just what they missed during a nasty contract dispute.

Jackson had a career-high three touchdown catches, Philip Rivers surpassed 4,000 yards passing for the third straight season and the Chargers beat Alex Smith and the San Francisco 49ers 34-7 on Thursday night to stay alive in the AFC West race.

The Chargers (8-6) pulled within a half-game of AFC West leader Kansas City (8-5), which lost 31-0 at San Diego on Sunday.

San Francisco was probably the toughest test left for the Chargers, who finish with games at Cincinnati (2-11) and Denver (3-10). If San Diego wins out and the Chiefs lose once, the Chargers will win their fifth straight division title.

The Chargers came within 4:26 of having consecutive shutouts for the first time in their 51-year history.

Jackson had his first three TD grabs of the season, of 58, 11 and 21 yards. Jackson missed the first 10 games due to a bitter contract dispute.

The 49ers (5-9) could wind up 7-9 and in a three-way tie and still win the NFC West, the NFL’s weakest division.

Rivers and Jackson came out early in the fourth quarter and the Chargers leading 31-0.

Rivers was 19 of 25 for 273 yards, giving him 4,141 for the season. He tied Hall of Famer Dan Fouts’ team record set from 1979-81.

Jackson had five catches for 112 yards.

Unhappy that the Chargers didn’t give him a long-term deal, Jackson sat out the first seven seasons. He then missed three more games while serving a team-imposed suspension. The move cost him some $3 million in salary.

When he returned at Indianapolis on Nov. 28, he pulled a calf muscle two plays in and was done for the night and the next game.

On the fourth play from scrimmage, Rivers wound up and threw deep. The 6-foot-5 Jackson slowed down and reached out over 6-foot Nate Clements’ head to make the catch at about the 15 before outracing the cornerback into the end zone.

Jackson exploited a mismatch against linebacker Takeo Spikes for an easy 11-yard catch just before halftime.

Jackson pulled in a 21-yarder early in the fourth quarter, getting the ball just past the pylon. The play was upheld after a review.

Mike Tolbert had a 1-yard TD run in the third quarter and Nate Kaeding kicked field goals of 25 and 39 yards.

Smith fell far short of having the happy homecoming he was hoping for. Coming off a promising return following a five-game absence, he was 19 of 29 for 165 yards with one interception and was sacked six times.

“We wanted it bad,” linebacker Brandon Siler said of the shutout that just eluded the Bolts. “We were saying on the sideline, ’Don’t give up anything cheap.’ It hurts a little bit, but I think we already know we’re a good defense. We proved that.”

San Francisco’s only score came on Brian Westbrook’s 3-yard run with 4:26 left.

“It’s so easy to go out and play defense and have fun when the offense is rolling,” defensive end Luis Castillo said. “We give them so much credit because it’s field position. It’s tiring out their defense, it’s getting us rested. You start to feel like you can do anything out there.”

The 49ers watched as both a field goal and a touchdown came off the scoreboard in a span of four plays early in the second quarter.

Jeff Reed kicked a 38-yard field goal but San Diego’s Antonio Garay was whistled for unnecessary roughness for trying to gain leverage, giving the 49ers first-and-goal at the 10. Smith scrambled and dove at the left pylon on third down and it was ruled a touchdown. The Chargers challenged and it was reversed, with Smith ruled down inches from the goal line. On fourth down at the 1, Siler threw Anthony Dixon for a 2-yard loss.

Smith was playing against his hometown Chargers for the first time in the regular season. He played at Helix High in La Mesa, where he was teammates with Reggie Bush. Chargers coach Norv Turner was the 49ers’ offensive coordinator in 2006 when Smith had his most promising season.

Michael Crabtree had just three catches for 17 yards and Pro Bowl tight end Vernon Davis didn’t have a catch until the waning minutes, finishing with one for 4 yards.

NOTES: The Chargers tied the team record for consecutive shutout quarters at seven. … 49ers DT Justin Smith was ejected after making contact with umpire Garth DeFelice following a play. The lineman, who has started 153 straight NFL games, was in an argument with at least one Chargers player when he appeared to shove DeFelice, who was trying to keep him out of the scuffle.