WASHINGTON -- It's been a frustrating season for Scott Diamond.
Diamond, who was the Twins' best starter as a rookie in 2012 with a 3.54 ERA in 27 starts, has failed to replicate his success this year.
It was more of the same on Sunday, as Diamond scuffled through just 4 2/3 innings, while the Twins' offense was stymied by Jordan Zimmermann in a 7-0 loss to the Nationals in the first game of a doubleheader at Nationals Park.
Diamond had a few bad breaks that didn't go his way, but ultimately gave up seven runs (six earned) on 10 hits and two walks to see his ERA rise to 5.19 in 11 starts this season.
"It was definitely a frustrating way to have the game turn out," Diamond said. "I thought I was executing pretty well. I thought the curveball was better than it's been. I was able to throw some pretty good changeups. So that outcome stinks. I'm pretty frustrated with the way it went."
Diamond cruised through the first three innings, but was hit hard in both the fourth and fifth innings.
Washington scored twice in the fourth, as Jayson Werth, Adam LaRoche, Ian Desmond and Anthony Rendon put together four straight singles.
It could've been more, if not for a strong throw from Clete Thomas in left field to throw out Werth at the plate on Desmond's single. But Desmond reached second on the throw and both LaRoche and Desmond scored on an infield single by Rendon, as shortstop Pedro Florimon made a nice stop but threw the ball past Justin Morneau at first for an error that allowed Desmond to score from second.
"Florimon made a really nice play there, but Morny needs to come off the bag there," Twins manager Ron Gardenhire said. "We talked about that. He wasn't sure if he had a chance to get the runner."
The Nationals put the game out of reach with a five-run fifth inning that saw them bring 10 batters to the plate. All five runs also scored with two outs.
Jeff Kobernus started it off with a leadoff walk with one out before Ryan Zimmerman doubled with two outs. The Twins opted to walk Werth to get to LaRoche but it backfired, as LaRoche hit a hard grounder to second base that Brian Dozier couldn't handle to bring home a run. The play was ruled a hit, but Gardenhire didn't agree with the scoring decision.
"That ball hit to second was an error," Gardenhire said. "This is the big leagues. He took two steps to his right. That's an error. It happens, but it was not a base hit. It's unfortunate."
Desmond followed with a two-run single that knocked Diamond out of the game in favor of rookie Ryan Pressly. But Pressly promptly threw a wild pitch on his first pitch and then surrendered a two-run double to Rendon just three pitches later. Pressly also exited in the sixth with right biceps soreness, but checked out OK after the game.
It was more than enough offense for Zimmermann, who threw seven scoreless innings against a lineup that didn't include Joe Mauer or Josh Willingham. Zimmermann gave up just two hits -- both to Chris Parmelee -- and walked two to go along with eight strikeouts.
"It means I'm pitching pretty well if I'm going deep in the ballgame," Zimmermann said. "I'm giving the team a chance. For the most part, they have scored quite a few runs for me. Hopefully, we can get another win tonight."
The Twins will turn to Samuel Deduno in the second game of the doubleheader, with Nate Karns starting for the Nationals. Deduno will look to get the Twins back on track, as Diamond's outing broke a streak of five straight quality starts for Minnesota.
"We have a good shot of getting back on the train with Sammy starting tonight," Diamond said. "I think with how aggressive the Nationals are and with the way he controls his curveball, we can get back on that train and get a quality start. It's just frustrating I was the one to end it."