SAN DIEGO -- If one looks at Matt Chico's record in professional baseball prior to the 2007 season, he never had a problem when it came to throwing strikes. In fact, Chico's career high in walks is 54 in 162 2/3 innings.

But it has been a different story during his rookie season with the Nationals. He has given up free passes to 20 batters in 27 1/3 innings. Having a tough time throwing strikes came back to haunt him on Wednesday night as the Nationals were defeated by the Padres, 7-3, in front of 22,153 at PETCO Park.

The Nationals have lost four of their last five games and dropped their record to 9-19.

It was a night in which Chico pitched in front of his hometown crowd. By the end of the night, Chico was baffled that he was having a tough time throwing strikes. He indicated that he has to try to fix the problem during bullpen sessions.

"It's something new to me right now because I never had control problems before. I have 20 walks," Chico said. "That's what is frustrating to me right now, because I never had control problems before."

Chico said he was not nervous on the mound and wasn't anxious pitching in front of his family and friends.

"Right now, I'm in the aiming stage. I'm trying to throw the strikes instead of just letting it go and trusting my stuff or [catcher Brian] Schneider back there," Chico said. "I treated Wednesday like any other game. It was just family in the stands. I had it plenty of times before."

Chico was cruising in his first three innings, and he was given a 1-0 lead in the first, but he found himself out of the game by the fourth.

With one out and a runner on first base, Khalil Greene tripled to right-center field to drive in Adrian Gonzalez to tie the score at 1. Chico then walked the next two batters to load the bases. Kevin Kouzmanoff gave the Padres a one-run lead when he hit a sacrifice fly to center fielder Ryan Church to drive in Greene.

Geoff Blum added to the lead when he brought home Josh Bard with a bloop single. Marcus Giles then doubled to drive in Mike Cameron and Blum.

"I lost control. I think I was concentrating too much on trying to throw strikes," Chico said. "I was starting to aim the ball a little too much instead of just throwing it."

Nationals manager Manny Acta felt Chico was trying to prevent the hitters from making contact. That isn't a good strategic move because PETCO Park is considered a pitcher's ballpark. Having the hitters make contact may have been the best thing for Chico.

"When you throw more balls than strikes at this level, things are going to happen," Acta said.

Chico's command wasn't the only problem on Wednesday night. The offense continued to struggle. After Padres starter Clay Hensley left after two-plus innings because of a right groin strain, the Nationals were unable to touch the bullpen until the seventh inning, when they scored two runs off Cla Meredith. Even that didn't go smoothly.

With Church on first, Schneider doubled down the left-field line. Church should have scored easily because outfielder Jose Cruz had trouble picking up the ball, but third-base coach Tim Tolman held him up.

Robert Fick followed, and he drove in two runs with a double. Kory Casto then doubled over the head of Cameron in center field, but Fick didn't score, believing that Cameron was going to catch the ball.

"I had a bad read. I thought he was going to catch it," Fick said.

The Padres scored two runs in the bottom of the eighth inning. Gonzalez homered off reliever Ray King, and Terrmel Sledge doubled home another run off Jesus Colome.