Chris Tillman and three Orioles relievers combined on a three-hit shutout of the Boston Red Sox, while Chris Davis tacked on another home run to his league-leading total in Baltimore's 2-0 victory over its AL East rival.
Tillman (7-2) scattered three hits and four walks over six-plus inning to win his fourth straight decision, while Darren O'Day, Tommy Hunter and Jim Johnson each worked an inning of relief to finish off the whitewash.
Davis hit a solo shot and Adam Jones legged out an infield single to knock in the other run for the Orioles, who have taken the first two meetings of this four-game set and have won five of their last six games overall.
The Red Sox lost back-to-back games for the first time this month as they went 1-for-7 with runners in scoring position and had just one extra-base hit.
Ryan Dempster (4-7) allowed two runs on five hits and five walks in 7 2/3 innings of work to take the loss.
Davis sent Dempster's up-and-away fastball over the left-field wall to open the second inning, pushing his total to 22 home runs on the year.
With two outs and runners on the corners in the third, Jones hit a tapper down the third-base line and beat out Will Middlebrooks' throw to first, allowing Nate McLouth to score for a 2-0 Orioles lead.
Tillman retired Middlebrooks and David Ross to strand two in the fourth and set down the side in order in the fifth and sixth innings.
He was pulled after surrendering a double to Jose Iglesias in the seventh, and O'Day retired the next three hitters to keep the Red Sox off the board.
After Hunter tossed a 1-2-3 eighth, Johnson erased a hit batsman by inducing a game-ending double-play ball off the bat of Iglesias to lock up his 24th save of the season.