KANSAS CITY, Mo. — The NFL's highest-rated passer would not be stopped.

Philip Rivers rallied San Diego from a 21-3 third-quarter deficit, throwing two touchdown passes in the final 73 seconds, and the Chargers stunned Kansas City 22-21 today.

The Chiefs, aided by a delay of game penalty against the Chargers, tried a 50-yard field goal on the final play, but Connor Barth's kick was wide left.

Pending the outcome of Denver's game later Sunday, the victory kept alive the slender playoff hopes of the Chargers (6-8), who came into the season as Super Bowl favorites after losing to New England in last year's AFC title game.

Rivers, who came in with an NFL-best 102.0 passer rating, was 34-for-48 for 346 yards with two touchdowns and one interception.

With the spare Arrowhead Stadium crowd ready to celebrate the Chiefs' third victory, Rivers led San Diego on an 89-yard drive, hitting Malcolm Floyd with a 4-yard scoring pass with 1:13 left, making it 21-16.

After the two-point conversion pass failed, the ensuing onside kick bounced off the chest of KC's Dwayne Bowe, and Kassim Osgood fell on the ball for San Diego at the Chargers 39.

Rivers' first play produced a 39-yard pass to Vincent Jackson to the 19. Then on third-and-1 from the 10, Jackson got open in the end zone and the Chargers seized the lead with 36 seconds left.

The Chiefs (2-12) held San Diego to 106 yards and 3 points in the first half, but the Chargers, behind Rivers, had 288 yards in the second.

Tyler Thigpen, the one-time third-teamer, threw for one touchdown and ran for another for the Chiefs. Thigpen, who took over when season-ending injuries claimed the top two quarterbacks, was 19-for-28 for 171 yards. In his last eight starts, the former seventh-round draft pick has 13 touchdown passes and five interceptions.

The Chargers had three turnovers and, perhaps more embarrassing, gave up three sacks to the NFL's worst pass rush. Tamba Hali had two sacks and caused two fumbles for a Chiefs defense that hadn't gotten a sack since playing San Diego four games ago.

The three sacks pushed KC's season total to a league-low nine, and the Chiefs need five sacks in their last two games to avoid tying the NFL record for fewest in a season.

Running back Larry Johnson capped a 96-yard drive with a 4-yard TD pass to Tony Gonzalez on KC's first possession. Then, after a series of San Diego mistakes, Thigpen hit Bowe with a 1-yard TD pass for a 14-0 lead.

Midway through the third quarter, Patrick Surtain, an 11-year veteran cornerback who had missed the previous six games with a knee injury, stepped in front of the receiver and intercepted Rivers' pass.

He chugged 50 yards before Rivers caught up and pushed him out of bounds at the 3, and Thigpen scored on the next play for a 21-3 lead.

LaDainian Tomlinson scored on a 6-yard run for the Chargers in the third quarter and Nate Kaeding had a 32-yard field goal in the second.