Orioles 6, Red Sox 5 (13 innings)
BALTIMORE -- Chris Davis lined a walk-off single in the bottom of the 13th inning that gave the Baltimore Orioles a 6-5 victory over the Boston Red Sox on Tuesday night.
Right fielder Gerardo Parra started the game-winning rally with a walk off Red Sox right-hander Jonathan Aro. Third baseman Manny Machado then lined a single to center, and Parra never hesitated, easily making it to third.
Left-hander Robbie Ross Jr. then came on to face first baseman Davis. On a 2-1 pitch, Davis lined his game-winning single to right, bringing in Parra to end the 4-hour, 20-minute marathon.
Right-hander Chaz Roe (3-2) earned the victory after blanking Boston in the 13th. Aro (0-1), who came on in the 11th, took his first major league loss.
The Orioles (71-73) now have won six of their last seven games, trying to keep playoff hopes alive. Boston (68-76) has dropped two straight.
Boston had tied the game at 5-5 when first baseman Travis Shaw led off the eighth with a home run of left-hander Brian Matusz. The Red Sox rallied from an early 4-1 deficit to force extra innings.
Orioles starter Ubaldo Jimenez was trying for his 100th career victory, but the right-hander struggled with his command again and lasted just five innings.
He left with a 5-4 lead thanks to Machado's solo homer in the fifth, but first baseman Travis Shaw erased that with his lead-off homer in the eighth off left-hander Brian Matusz.
The Red Sox took a 1-0 lead in the third when first baseman Travis Shaw drew a two-out bases-loaded walk off Jimenez.
The Orioles answered with four runs in the bottom half. Pearce started things with a two-run homer to left.
Baltimore added another run when first baseman Chris Davis singled to center, but Betts' relay throw got loose on the Boston infield. That error let Machado score from third.
Kelly came out after giving up a single to center fielder Adam Jones. Davis then scored when catcher Matt Wieters greeted left-hander Craig Breslow with a sacrifice fly that gave the Orioles a 4-1 lead.
The Red Sox then tied it with three off Jimenez in the fifth. Their first three batters got hits, the last being an RBI single from shortstop Xander Bogaerts. Designated hitter David Ortiz followed with a sacrifice fly.
That cut the lead to 4-3 before third baseman Pablo Sandoval later added an RBI single. Sandoval initially was ruled safe at second before Orioles manager Buck Showalter challenged it, and the play got overturned for the inning's final out. Pearce made a good throw to second to nail Sandoval.
Machado then lined a one-out solo homer off Breslow in the bottom of that inning to put the Orioles back on top, 5-4.
NOTES: The Orioles recalled RHP Tyler Wilson, RHP Oliver Drake, INF Christian Walker and OF Junior Lake from Triple-A Norfolk on Tuesday. All four have played with the Orioles at various points this season. ... Orioles manager Buck Showalter said Norfolk manager Ron Johnson and pitching coach Mike Griffin will join the team starting with Monday's series in Washington. Norfolk was just eliminated from the International League playoffs on Monday night. ... Boston interim manager Torey Lovullo said 2B Dustin Pedroia will be in the starting lineup for the final two games of the series. The Red Sox gave him a break Monday to be careful with his hamstring, which kept him out for 42 games before returning Sept. 8. ... The series, which ends Wednesday, is the Red Sox's final visit to Camden Yards this year. The teams meet once more in Boston on Sept. 25-27.