WASHINGTON -- Left-hander Odalis Perez may have pitched his last game at Nationals Park. If so, the free-agent-to-be gave the hometown fans a quality start.

Unfortunately, Perez didn't get the win, as the Padres defeated the Nationals, 6-2, on Sunday afternoon.

Perez pitched six innings, giving up three runs on five hits. He also struck out a career-high 11 batters.

However, Perez experienced two bad innings. In the first, Perez gave up a two-run double to Kevin Kouzmanoff. Five innings later, Adrian Gonzalez hit a home run.

"The first inning, I made a couple of mistakes," Perez said. "They scored a couple of runs. Unfortunately, in the sixth inning, I made another mistake, and I allowed the home run. Everything else was working pretty much -- fastball, changeup, slider. The cutter was pretty good. I felt good all day long. What can I do? I had a quality start."

This season has been a comeback for Perez. Last year, he struggled with the Royals, going 8-11 with a 5.57 ERA. He acknowledged during Spring Training that his confidence was waning during his time with Kansas City, though he would never say what caused that drop.

During the offseason, Perez had a tough time finding a job. It took until Spring Training for the Nationals to offer him a Minor League contract. Perez took the deal, but ended up being the Opening Night starter against the Braves at Nationals Park.

Overall, it's safe to say that Perez exceeded the Nationals' expectations. He delivered 14 quality starts and a respectable 4.27 ERA.

"[Perez] has done a very god job," manager Manny Acta said. "He has given us a lot of quality starts and the innings that we were hoping he would give us out of Spring Training. We think he could have easily won double digits, almost 15 wins, with any type of help."

Whether Perez stays with Washington beyond 2008 is an open question. He said he plans to stay in D.C. until December because his wife is pregnant and will give birth in the District. Perez will then return to the Dominican Republic to play winter ball.

"If I have the opportunity to come back to Washington, I will do so," Perez said. "The way I've been treated here has been great. I have respect for Manny, the coaching staff and the players. Unfortunately, we didn't win a lot of games because of the injuries that we had. For my part, it has been great."

Padres right-hander Cha Seung Baek is the main reason the Nationals didn't get the victory on Sunday. He lasted seven innings, giving up just one run on five hits. That lone run came in the sixth inning on a Ryan Zimmerman homer.

"Today, I thought his hard cutter and hard slider were very effective to both right- and left-handed hitters," Padres manager Bud Black said. "Then I saw effective use of his changeup. He's a guy who has quality Major League pitches."

San Diego added to its lead in the eighth inning. With Garrett Mock on the mound, Edgar Gonzalez reached base on an error by Zimmerman, who threw the ball wide to first baseman Kory Casto. The replay showed that Casto made the tag before Gonzalez reached base, but first-base umpire Paul Emmel said Casto tagged Gonzalez at the same time the latter touched the bag.

"[Emmel] just blew it," Acta said. "It was a bad call. Unfortunately, it didn't help us."

The flood gates opened after that. With Saul Rivera on the mound, Kouzmanoff drove in Edgar Gonzalez with a single, while Chase Headley knocked in Adrian Gonzalez with a single to center. Only one of the runs were charged to Mock.

Rivera would be charged with a run later in the inning, when Kouzmanoff came home on a sacrifice fly by Nick Hundley.

Zimmerman drove in the Nats' second run in the eighth with a single to left that brought home Ryan Langerhans from second.

The Nationals have lost five straight games after being swept by the Padres.

"They got more big hits than us," Zimmerman said. "We didn't play good enough to win. If you don't play good enough to win in this league, you are going to get beat."