Dempster continued the rotation's brilliant stretch of starting pitching. He gave up three runs on just four hits, including solo home runs to Adam Kennedy and Adam Dunn. But it was still too much for Chicago's offense to overcome.
"It's a loss regardless," Dempster said. "We win and lose as a team, and at the end day, there's an 'L' beside our name.
"I felt like I could've done a better job. I gave up a base hit with a pitcher on deck, and I gave up a solo home run to a guy in the lineup you don't want to let beat you."
After Dunn gave the Nats a 3-2 lead with his blast in the fourth, the Cubs missed out on numerous scoring chances, particularly in the fifth. Chicago had the bases loaded with one out, but Marlon Byrd and Mike Fontenot couldn't get the ball out of the infield.
"I had the bases loaded, one out ... I got to be big there," Byrd said. "All year long, I've been getting it done. I have to get the ball to the outfield some way, somehow."
Byrd did lead off the eighth with a double, but was left stranded. Still, he only wanted to focus on the earlier missed opportunity.
"Bases loaded, less than two outs ... I have to get that run in," Byrd said. "Bottom line. There's no excuse not to. We're big leaguers. There's no reason not to get that run in."
It certainly wasn't all negative for Byrd, who made an unbelievable catch on a ball in center that he appeared to lose in the sun. At the last minute, he stuck his glove out and was able to snare the fly ball behind his back.
"It was one of those see-it-at-the-last-minute-the-sun-was-in-your-eyes [catches]," he said.
"It looked like he just stuck out his glove backward and it went in it," first baseman Derrek Lee said.
Manager Lou Piniella didn't have much to say in the postgame news conference, other than to reiterate that the Cubs' offensive deficiencies are growing tiresome.
"We should be able to get some people in," Piniella said. "We get some people on; you should be able to get them in."
"We didn't get the big hit," Lee said. "We gave ourselves a couple opportunities and didn't pull through.
"It doesn't help that I'm not getting on base and driving guys in sitting in the middle of the order. I could start pulling my weight as well."