BALTIMORE -- Right-hander Jordan Zimmermann was dominant for six innings, but then lost it on one pitch in the seventh as the Nationals fell to the Orioles, 2-1, at Camden Yards on Sunday afternoon.
It was the same old story. A Nationals pitcher must be perfect on the mound because the offense has been missing in action all year. Washington has the worst offense in the National League with a .229 batting average.
Zimmermann was almost perfect. Over the first six frames, Zimmermann allowed one hit -- a double to Mark Reynolds -- and had a 1-0 lead. The run scored in the fourth inning, when Jayson Werth touched home plate on an infield single by Alex Cora.
"I felt great [all afternoon]," Zimmermann said "The curveball was good. I felt like I could throw it wherever I wanted to."
Orioles manager Buck Showalter came away impressed with Zimmermann's performance.
"His secondary pitches were pretty impressive today," Showalter said. "He threw a lot of tight sliders and mixed in the changeup enough. He was impressive. You can see why they're so high on him. He's got a good arm. They've got a lot of great arms down there."
The Nationals struggles on offense continued, however. They were 1-for-8 with runners in scoring position.
"It's more of the same," manager Jim Riggleman said. "I'm glad we got baserunners out there. That's better than not having them out there, but we are just not getting them in. That's too bad, because we got another good pitching performance.
"You can play the tape from many other games. I'm proud of our guys for the way they battle and the way they play. They play good, clean baseball. We pitch well. Guys are giving me 100 percent when they step in that batter's box, but it just hasn't happened."
The Nationals had numerous chances to score runs. In the first inning, Riggleman was ejected from the game.
On the game's second pitch, it appeared that outfielder Roger Bernadina bunted for a base hit, but home-plate umpire Todd Tichenor called Bernadina out for stepping out of the batter's box while trying to bunt.
At first, Riggleman thought Bernadina was called out for running out of the baseline. A few seconds later, Riggleman learned that Bernadina stepped on home plate while he was bunting.
Riggleman argued for several minutes with Tichenor before being tossed. It marked the second time Riggleman was ejected from a game this season. The skipper looked at the video later and realized that Tichenor was right. Bernadina's foot was on home plate during the bunt.
"It's like most calls: [The umpires are right] and we are wrong," Riggleman said. "I didn't even have an argument. I was just irritated the call was made. ... But it's a call you just never see get made. He got the call right. I don't know what else I could say."
After Bernadina was called out, Ian Desmond was the next hitter, and he doubled over the head of center fielder Adam Jones with one out, but Laynce Nix struck out and Jayson Werth grounded out to end the inning.
Washington's biggest chance to break the game open occurred in the third inning off Orioles starter Chris Tillman. The Nationals had runners on second and third with one out, but both Desmond and Nix struck out to kill the rally.
"We have second and third with one out. I'm feeling good about what's going to happen. We just didn't get the hit," Riggleman said.
Zimmermann wasn't near perfect for long. In the seventh inning, the young right-hander, who was pitching on nine days' rest, ran intro trouble. After Nick Markakis singled to right field, Vladimir Guerrero took an 0-2 pitch and homered over the left-field wall for his fifth homer of the season, which gave Baltimore the one-run lead.
On that pitch, Zimmermann tried to throw a curveball in the dirt, but the pitch stayed up and Guerrero crushed the ball.
"The pitch just hung up a little bit," Zimmermann said. "He is a tough hitter to pitch to. You have to mix it up. I threw balls in the dirt. I threw them high. You have to pretty much mix it up and hope for the best."
After allowing a single to Luke Scott with one out, Zimmermann was taken out of the game in favor of Tyler Clippard, who found himself in trouble after allowing a single to J.J. Hardy and walking Robert Andino to load the bases. But Clippard managed to strike out Felix Pie to end the inning.
The Nationals couldn't rally off Orioles closer Kevin Gregg in the ninth, losing their 25th game of the season.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.