McLouth also made a leaping catch against the left-field wall to save a run.
Matt Wieters knocked Chamberlain out of the game with a broken-bat single to lead off the 12th inning that struck his surgically repaired right elbow. Fans sat silent as Chamberlain bent over in pain. He was checked out by trainer Steve Donahue and Girardi.
Chamberlain tested the elbow with three pitches before walking off the field. X-rays were negative. He's not sure if he'll be available for Game 5.
"You kind of see how it feels and go from there," Chamberlain said. "It's definitely not as stiff as it was when it first happened."
Many of the Orioles gathered near their bat rack in the dugout for an impromptu cheer before the 13th and Machado then led off with a double.
One out later, Hardy hit a one-bouncer off the wall in left field for his first RBI of the series.
The hit came after another Orioles quirk — the players held Gatorade bottles and wiggled them in the dugout, trying to conjure up a rally.
Showalter professed confidence in the 51-save Johnson before the game. He backed it up by calling on him for his fourth appearance of the series. Johnson lost the opener after giving up five runs in the ninth and sandwiched saves around his trying homer to Ibanez.
Seven Baltimore relievers pitched 7 1-3 innings of four-hit ball.
"There's really good pitching," Girardi said. "You're seeing some really good pitching in these four games."
Baltimore needs it because its top hitters are missing a lot. Mark Reynolds is 3 for 16. Hardy is 3 for 18. Wieters is 2 for 17 and Adam Jones is 2 for 19.
The Yankees held a moment of silence for Girardi's dad, Jerry, who died Saturday at 81 and had a long bout with Alzheimer's. Joe Girardi stood alone in front of the Yankees dugout and wiped his eyes after the national anthem. He blew a kiss to someone in the stands, then fist bumped several coaches and players.
Facing elimination for the second time this postseason, Showalter turned again to Joe Saunders. Acquired by Baltimore on Aug. 26 from Arizona, Saunders pitched 5 2-3 innings of one-run ball in the wild-card win over Texas.
He was just as crafty against New York, engaging with Hughes in a duel of who could get out of the tougher jam.
The Yankees put a runner on in every inning against Saunders but failed to score until the sixth.
Derek Jeter lined an outside pitch to right field for a leadoff double in sixth, showing no ill effects of a bruised left foot that kept him from playing shortstop in the postseason for the first time in his career.
He advanced on Ichiro Suzuki's sacrifice and scored on Robinson Cano's grounder to second. Showalter then lifted Saunders for right-hander Tommy Hunter to face Rodriguez. A-Rod struck out to loud boos and tossed his bat.
Rodriguez is 2 for 16 (.125) with nine strikeouts in the series.
NOTES: Curtis Granderson has struck out nine times in 16 at-bats this postseason. ... Hughes and Saunders combined to walk seven after there were no walks Wednesday in 12 innings.
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