Nate McLouth led off the bottom of the first with a home run and the Orioles went on to score twice more in the inning en route to a 6-3 victory over the Boston Red Sox, giving Baltimore a sweep of the three-game series at Camden Yards.
J.J. Hardy and Chris Davis also homered for the Orioles, who have won four in a row and maintained a share of the AL East lead heading to St. Petersburg for a three-game set with the Tampa Bay Rays to conclude the regular season. The New York Yankees kept pace with Baltimore thanks to a 9-6 win at Toronto on Sunday.
The Orioles and Yankees, though, each clinched a playoff spot later on Sunday after the Texas Rangers split a doubleheader with the Los Angeles Angels of Anaheim.
Jim Thome contributed a pair of run-scoring singles in the victory, while Joe Saunders pitched 7 1/3 solid innings for his first win in four starts.
Saunders (3-3), in his seventh outing for Baltimore after being acquired from Arizona in late August, yielded three runs on eight hits with no walks and five strikeouts.
"It was very humbling," said Saunders, who left the field to a standing ovation. "I've always tried to pride myself in stepping up in that situation and do my best."
Cody Ross belted a solo homer and Daniel Nava added a two-run shot for the Red Sox, who have lost five in a row and nine of their last 10. Boston has reached 90 losses for the first time since finishing the 1966 season at 72-90.
The Red Sox will now try to help the Orioles, as Boston heads to New York to wrap up the campaign with three against the Yankees.
Zach Stewart (1-4), in his second start for the Red Sox, was roughed up for five runs on seven hits in just 2 2/3 innings. Stewart was one the players the Red Sox acquired from the White Sox in the deal that sent Kevin Youkilis to Chicago.
"Those guys are basically on the gas pedal right now and they're doing a good job," Stewart said about the Orioles. "I didn't feel like I was very consistent."
McLouth started the game with his 10th career leadoff homer, a blast over the left field wall, and the Orioles went on to load the bases with no outs on a pair of singles and a walk. Matt Wieters bounced into a double play to score one and Thome beat the shift with a weak ground ball through the vacated left side of the infield to plate another for a quick 3-0 lead.
Hardy led off the third with his 22nd homer and Thome added a run-scoring base hit later in the inning.
Boston got one back in the fourth when Ross led off the inning with his 22nd home run, but Davis got that run back in the fifth with his 31st homer. Nava connected for his fifth homer of the season, a two-run shot in the seventh, to draw Boston within 6-3.
The Red Sox didn't seriously threaten over the final two innings and Jim Johnson worked a perfect ninth for his 50th save of the year. He became the 10th pitcher to reach 50 saves in a season.
Saunders, who is 9-13 overall this season, improved to 5-2 lifetime against Boston ... Baltimore finished 47-34 at home ... The Orioles were 13-5 against the Red Sox this season, including 6-3 at home ... Adam Jones was voted the Orioles' MVP by members of the local media, winning the award for the second straight season.