BALTIMORE -- Brad Bergesen struggled with the humidity and his command. His mechanics were spotty, his breaking ball ineffective.
And yet, the rookie right-hander was still plenty good enough to beat the Washington Nationals.
Bergesen allowed four hits in six innings to win his fourth straight decision, Melvin Mora had four RBI, and the Baltimore Orioles used an eight-run sixth to cruise to an 11-1 victory Friday night.
Bergesen (5-2) gave up one run, struck out five and walked two. He's 4-0 in six starts since May 24 and is tied with Jeremy Guthrie for most wins on the team.
"I think my only smooth inning was that last one," Bergesen said. "Seemed like I would get two outs and then walk a guy or hit a guy and get runners in scoring position. The whole night seemed like an absolute battle."
And still, he limited the Nationals to one run.
"Brad Bergesen pitched with his heart tonight. He struggled to get through it," Baltimore manager Dave Trembley said. "You saw so many three-ball counts early in the game, which was really uncharacteristic of him."
Asked if Bergesen has emerged as the most consistent starter in the rotation, Trembley replied: "That's a fact. Look at the numbers. Look at what he does. He is."
Aubrey Huff drove in three runs, and Nick Markakis, Adam Jones and Nolan Reimold each had three hits for the Orioles, who sent 13 batters to the plate in taking an 11-1 lead in the sixth.
Washington, which owns the worst record in the majors, finished with seven hits.
"Our offense has been scuffling. Bergesen kept us off balance and kept the ball low," manager Manny Acta said. "They beat us in every way -- pitching, hitting and defense."
A crowd of 45,024 -- the biggest at Camden Yards since opening day -- showed up for this interleague matchup between last-place clubs. The Orioles were coming off a three-game sweep on the road by the Florida Marlins, and needed a solid effort from Bergesen to get back on track.
The rookie delivered.
"Tonight was such a battle for me -- the humidity and then getting in late last night," Bergesen said. "So to get the first win in the series is huge."
Dropped two slots in the batting order to seventh because of a lack of production, Mora came in with 18 RBI -- including a mere three in June. After hitting a run-scoring single in the fourth inning, he drove in three runs in the sixth with a two-run double and a sacrifice fly.
"Melvin had some classic at-bats tonight. Even his last one, with the score being what it was, he wanted that RBI," Trembley said.
Ross Detwiler (0-4) allowed five runs and nine hits in five-plus innings for Washington. The former No. 1 draft pick has gone eight starts this season without earning his first big league win.
Asked to assess his performance, Detwiler said: "Terrible. I left the ball up all game. That's why they had nine hits and were hitting it hard all night."
The Orioles used a two-run fourth inning to take a 3-1 lead, but were left wanting more. After Huff scored on an error and Mora hit an RBI single, Baltimore loaded the bases with no outs. Robert Andino then hit into a 5-2-3 double play and Brian Roberts grounded out.
But the Orioles got all the runs they needed in the sixth. Reimold, who took over for Mora in the fifth spot, started the uprising with a single and later received a walk. Other highlights: A two-run single by Huff, and RBI singles by Luke Scott, Jones and Markakis.
Much of the damage came against reliever Joel Hanrahan, who yielded four runs, three hits and a walk, leaving his ERA at an unsightly 7.71.
"It's very frustrating," he said. "I know I'm better than this."
Baltimore set the tone in the first inning when Jones doubled and scored on a sacrifice fly by Huff. Washington used singles by Adam Dunn, Elijah Dukes and Josh Bard to pull even in the second.
Bard went 2 for 3 and is batting .400 (18 for 45) in June. ... The eight-run inning tied the Orioles' high for the season, set on May 9 against the Yankees. ... Orioles RHP Koji Uehara will probably miss his scheduled start Sunday because of right elbow soreness.