SAN DIEGO, Calif. -- The Dallas Cowboys were sharp and showed a glimpse of their potential for almost 10 minutes against San Diego.The rest of the night with the backups was a lost display of turnovers, breakdowns and lack of play-making. San Diego pounded the mostly-listless Cowboys 31-17 Saturday night at muggy Qualcomm Stadium in the preseason opener for both teams.One drive by the starting offense and defense was about all Wade Phillips could be happy with. It could force him to dial up training camp workouts this week to address the execution issues of the reserves.Dallas had an interception (by backup Brad Johnson), fumble (by punt returner Danny Amendola) and five penalties in the first half. The two turnovers led to San Diego touchdowns.The Cowboys offense only operated with all of its stars for one quarter before Wade Phillips pulled the plug. Quarterback Tony Romo, tight end Jason Witten, running back Marion Barber and receiver Terrell Owens only played in the opening drive.It was the only real sign of success from the offense. Dallas took a 7-0 lead with 8:14 left in the first quarter as quarterback Romo dissected the Chargers defense with an 8-play, 54-yard drive. The offensive energy on its first drive came after the Cowboys defense held the LaDainian Tomlinson-less Chargers to a three-and-out. Fullback Deon Anderson finished off the drive on a two-yard touchdown.Romo ended 3-for-3 passing with 33 yards. Barber had four carries for 24 yards including a 15-yard burst.I felt like weve had a really good camp and it was good to see that carry over tonight when the game starter, Romo said. Were a confident group and we feel like when we get the ball we have a good chance to score.Nose tackle Tank Johnson, considered to be a big contributor this season, had a sack on his first play of the game chasing down Chargers quarterback Philip Rivers. The defensive starters played just the first two series.I thought defensively we came out and had a good start, linebacker Greg Ellis said. We have a while before well have everything go the way we want it to go, and we have some work to do. But its still early.The night went downhill for the Cowboys with 5:26 in the first quarter when Amendola fumbled. The Chargers recovered at Dallas 31 and scored five plays later to tie the game at 7-7. The Cowboys energy appeared lost as an avalanche of mistakes, coverage problems and missed plays followed.Rookie first-round pick Felix Jones showed something special on his first NFL carry. He busted outside and cutback on the Chargers first-team defense with a 19-yard carry. Jones also took a short pass for a 28-yard gain in the second quarter.Jones finished with six carries for 32 yards after replacing Barber.While the rookie stood out, the other big-name Jones struggled. Pacman Jones, in his debut with the Cowboys, gave up more plays than he made. During the first quarter, he was beaten by Chris Chambers for 21 yards, whiffed at a tackle on running back Darren Sproles and had a pass interference call in the third quarter that negated a Patrick Watkins interception. The 18-yard penalty moved the ball to the 4-yard line and set up a touchdown two plays later.Rookie Tashard Choice gave the offense a spark after replacing Jones. He had a 19-yard touchdown run to cut the deficit to 31-17 with 4:32 left in the third quarter.Third-string quarterback Richard Bartel played the entire second half and finished 7-of-15 for 64 yards.An announced crowd of 61,946 was on-hand to watch the game.