Rivers threw two touchdown passes, including a 22-yarder to All-Pro tight end Antonio Gates midway through the third quarter that lifted the San Diego Chargers to a 23-13 victory over the slumping Super Bowl champions.

Gates' catch capped a remarkable 91-yard drive during which Rivers, in his first year as a starter, threw nine passes in the span of 10 plays, completing six.

San Diego (3-1) got its coach, Marty Schottenheimer, off the hot seat. Schottenheimer, whose conservative approach has long been known as ``Martyball,'' was heavily criticized after sitting on a 13-7 halftime lead a week earlier at Baltimore. The Ravens rallied to win 16-13.

The Steelers (1-3) have lost three straight games for the first time since late last season. They recovered then to earn a wild-card playoff spot, then went on to win the Super Bowl. The Steelers were shut out in the second half and gained just 49 yards after intermission.

Rivers and Ben Roethlisberger were two of the top three quarterbacks taken in the 2004 draft. While Roethlisberger helped beat the Chargers here 24-22 last year when Drew Brees was San Diego's starter, his return was a lot more painful.

While Roethlisberger looked sharp in directing three scoring drives in the first half, he also was pressured most of the night. He threw two more interceptions, giving him seven this season, and was sacked five times. He has yet to throw a touchdown pass this season and finished 20-of-31 for 220 and two interceptions.

On a colourful night when the Chargers wore their powder blue throwback jerseys and Steelers fans waved yellow Terrible Towels _ at least early on _ Rivers started slow and finally got the upper hand.

San Diego's go-ahead drive was set up when Roethlisberger threw long to rookie receiver Santonio Holmes on a flea-flicker and was intercepted by Drayton Florence. Florence returned it to the Pittsburgh 38, but Steelers coach Bill Cowher challenged and, after a review, referee Bill Vinovich ruled the cornerback had been down by contact at the nine-yard line.

LaDainian Tomlinson carried for one yard on the first play and took a lateral for 12 yards on the sixth play, but otherwise the Chargers went to the air. Rivers had two big completions to Eric Parker, as well as passes to Tomlinson and Keenan McCardell.

Gates, mostly a forgotten man this season, finished it off when he outmuscled cornerback Deshea Townsend, then dived into the end zone for a 17-13 lead.

On San Diego's previous possession, Schottenheimer showed his conservative side when, on fourth-and-1 from the Pittsburgh 10, he was content to settle for Nate Kaeding's 28-yard field goal that pulled the Chargers to 13-10.

Rivers was 4-for-7 for five yards in the first quarter. He was 19-of-29 for 226 yards in the last three.

Roethlisberger helped the Steelers to a 13-7 halftime lead.

Willie Parker scored on a nine-yard run with 35 seconds left in the first quarter and Jeff Reed kicked field goals of 39 and 44 yards in the second period.

San Diego finally woke up after a lethargic start, with Rivers leading an 80-yard scoring drive capped when six-foot-five Malcolm Floyd outjumped 5-10 Townsend for a nine-yard catch in the left corner of the end zone with 1:11 left.

Rivers was intercepted on San Diego's first drive when Ryan Clark wrestled the ball away from Eric Parker.

Kaeding kicked field goals of 33 and 22 yards in the fourth quarter.

Tomlinson gained only 36 yards on 13 carries and had eight catches for 34 yards.