SAN DIEGO (AP) _ Free-agent running back Kevin Scott ran 74 yards for a touchdown and and quarterback Mark Herrmann threw a scoring pass as the San Diego Chargers beat the injury-weakened Dallas Cowboys, 29-0, in an exhibition opener Saturday night.

Scott took the ball through the middle of the line broke into the clear and sprinted down the field for the game's final score.

The game was marked by two reversals by the instant replay officials, both in Dallas' favor.

The second reversal involved a fourth-quarter pass from rookie Dallas quarterback Kevin Sweeney to wide receiver Cornell Burbage, who caught the ball for a 28-yard advance but then fumbled near the sideline with a San Diego player recovering.

The call awarding Chargers' possession at their own 26, was overruled by instant replay officials who determined that safety Walter Harris was out of bounds with the recovery.

It was the second straight preseason game where the Chargers blanked the Cowboys. Last year at a game in San Diego's Jack Murphy Stadium, the Chargers defeated the Cowboys 20-0.

Herrmann started for San Diego in place of the injured and disgruntled Dan Fouts, who had not practiced because of a sore back. Fouts and Chargers management are feuding over Fouts' contract status and Chargers owner Alex Spanos has threatened to trade him.

The Cowboys had a good chance to get on the scoreboard early in the fourth period but free-agent place-kicker Brian Franco missed a 36-yard field goal attempt.

Prior to the field goal, an apparent fumble by rookie running back Alvin Blount was overruled by the instant replay officials and the Cowboys kept the ball at the Chargers' 24 yard line. Blount was ruled down before the fumble. Two plays later, Franco attempted the field goal.

A second field goal by free-agent place-kicker Vincent Abbott, a 39-yarder, came with 3:02 remaining. The field goal was set up by defensive back Kevin Wyatt's interception of Sweeney. Wyatt returned the ball 14 yards to the Cowboys' 34 and the Chargers advanced the ball 13 yards before kicking the field goal.

Frank Middleton, trying out for a third NFL team, capped a 27-yard drive when he dove into the end zone late in the third period. Middleton played for Indianapolis in 1984 and part of 1985 and then had a training camp trial with Tampa Bay last year before joining the Chargers this season.

The Chargers and Cowboys played through a scoreless first period before San Diego quarterback Mark Herrmann threw a 17-yard touchdown pass to running back Lionel James with 21 seconds gone in the second quarter.