Aubrey Huff drove in the tiebreaking run with a pinch-hit triple in the seventh inning, and Baltimore capitalized on another poor performance by the Nationals bullpen in a 2-1 win Saturday night.
With the score 1-all, Huff stepped to the plate against left-hander Ron Villone with a runner on first and two outs in the seventh. Huff didn't start because he was mired in a 1-for-18 slump and was batting .157 against lefties this season.
Throw in the fact that Baltimore pinch hitters were 1 for 18 this season, and the chances of Huff getting the winning hit seemed remote.
"I've been struggling the last four or five games," Huff acknowledged. "To be able to get that hit against a left-hander was a little bit more satisfying because I haven't hit well against them this year."
Although the Orioles are in the AL East cellar and Washington owns the worst record in the majors, the Nationals drew their second-largest crowd of the season (31,833) for this interleague matchup of teams located 40 miles apart on the Baltimore-Washington Parkway.
The Orioles will seek to complete a three-game sweep Sunday.
Making his second major league start, 23-year-old Ross Detwiler pitched six innings of one-hit ball for Washington. The lone hit against the left-hander was an infield single by Nick Markakis that drove in a run.
As soon as Detwiler left, Baltimore took the lead against a bullpen that came in 2-16 with a 6.42 ERA.
"Villone just left a fastball up and out over the plate and Huff hit it hard," Washington manager Manny Acta said. "But he's been pitching good, and [the relievers] were able to keep us in the game. You're just not going to win too many games when you only score one run."
Bass (3-1) pitched three innings of three-hit relief after replacing starter Koji Uehara, who blanked Washington for three innings before leaving with left hamstring tightness. It's the same injury the Japanese right-hander had during spring training.
"It's not as bad," Uehara said through an interpreter. "I have a history of hamstring problems. It's been a long friendship in a sense so I know when not to go out and pitch."
Orioles manager Dave Trembley said, "I don't think it is serious, but I sure am going to be saying my prayers tonight because he is so important to us."
George Sherrill struck out the side in the ninth for his ninth save and second in two nights.
Cristian Guzman homered for the Nationals and third baseman Ryan Zimmerman went 1 for 3 to reach base in a 41st consecutive game. The single-season franchise record is 42, held by Tim Raines of the Montreal Expos in 1986.
The Orioles took the lead in the third without hitting the ball out of the infield. After Detwiler issued three walks, including a four-pitch free pass to Uehara, Markakis hit a slow roller to Zimmerman. The grounder turned into an RBI single when second baseman Willie Harris failed to cover the bag, leaving Zimmerman no choice but to hold the ball.
"Zimmerman knew all the way that Harris wasn't going to be there," Acta said. "He was playing Markakis to pull and he had already told Zimmerman that on a ball to him, he should go to first base."
Guzman tied it in the fifth with his second homer of the season, a shot to right that landed in the Washington bullpen.
Washington CF Justin Maxwell robbed Adam Jones of a homer with a leaping grab at the wall in the first inning. ... Uehara is 0-3 in seven starts since April 13. ... Nationals C Jesus Flores, on the 15-day disabled list with a right shoulder contusion, took early batting practice Saturday and is scheduled to being a minor league rehabilitation assignment Monday, Acta said.