NEW YORK -- The Yankee Stadium crowd grew quiet as the night went on, save for the occasional boos.
The New York Yankees had started Tuesday's game flexing their muscles as they had all year, pounding the Baltimore Orioles for five runs in the first inning.
The Yankees appeared poised to end their three-game losing streak and humble the second-place Orioles with a familiar display of their firepower.
But Baltimore instead left the Yankees grasping for answers, immediately responding with a seven-run second on the way to an 11-5 rout that looked anything but familiar.
The jolt of a comeback victory gave the upstart Orioles their second straight win over the Yankees and moved them within 5 1/2 games of the AL East leaders. New York dropped its ninth game in the last 12.
Chris Davis provided the big blow with a grand slam, and Nick Markakis added a two-run homer and his second consecutive three-hit, two-RBI game for the Orioles. Wilson Betemit also had three hits, his second straight multi-hit game against the Yankees.
Ivan Nova (10-5) allowed a career-worst nine runs to blow the early 5-0 lead built against Chris Tillman (4-1). The Orioles righty didn't allow a run after the first, combining with three relievers to shut out the Yankees in the final eight innings.
"It feels pretty big," said Orioles reliever Troy Patton, who pitched two scoreless innings. "We'll see what it amounts to, but it's important for us to get rolling and win some games against the best team in the league."
The Yankees' spot atop the American League has been threatened by their recent dip, and the stunning turnaround Tuesday didn't help.
"Well, we're not playing well, I mean, there's no doubt about it," Yankees manager Joe Girardi said. "We've been through streaks before where we haven't played well and bounced back, and that's all we need to do."
Robinson Cano hit his 23rd home run of the season for the Yankees, and Derek Jeter had three hits.
Markakis' two-run homer in the eighth put the finishing touches on the impressive win. The Orioles, who have not reached the playoffs since 1997, remained two games behind in the wild-card race.
Nova stunned the crowd and prompted boos after blowing the Yankees' 5-0 lead in the second inning, all with two outs.
Despite the quick lead for the Yankees with a 10-game winner on the mound, Betemit said the Orioles did not flinch.
"What nervous?" Betemit said, when asked if the early deficit made his team nervous. "We play every day. We don't have to be nervous."
Baltimore sent 10 men to the plate and racked up six hits during the seven-run, second-inning onslaught. Nova appeared set for his second consecutive scoreless inning after two strikeouts followed two hits, but Baltimore strung together three straight hits, including an RBI double by Mark Reynolds and a two-run single by Omar Quintanilla, to cut the deficit to 5-3.
After a walk loaded the bases, Davis punctuated the inning with an explanation point. He drove an 0-1 pitch off the top of the fence and into the Orioles bullpen in left-center for a grand slam and a 7-5 lead.
"Felt great," Davis said, playfully lowering his head to speak directly into a reporter's digital recorder to confirm it was his first career grand slam. "I was just hoping it'd get off the wall, and it did get off the wall, into the bullpen, so that was awesome."
The next inning, Lew Ford smacked his first hit since Sept. 21, 2007, a double to right, and scored when Betemit also doubled, giving Baltimore an 8-5 lead.
Despite the poor outing, and Girardi's terse assessment that Nova "just didn't have good stuff tonight" and unraveled, the starter said he didn't think he was that far off.
"I just had a bad day, but I don't feel that way," he said when asked if he lost focus. "I feel really good. I just got hit ... It was a bad day, bad luck. It was a tough day for me. I threw a lot of good sliders, good curveballs, and they got base hits."
The Yankees seemed set to end their losing streak early, jumping on Tillman for five runs in the first. Cano hit a two-run homer, and Tillman's error helped add to another run as the Yankees racked up six hits in the inning.
NOTES: The Yankees acquired infielder Casey McGehee, along with cash, from the Pittsburgh Pirates for reliever Chad Qualls. McGehee, who hit .230 with eight homers and 35 RBI in 92 games, will help fill in for injured third baseman Alex Rodriguez and first baseman Mark Teixeira. ... An MRI on Teixeira's injured left wrist revealed inflammation, the Yankees announced. Teixeira said he hoped to play by Friday in a best-case scenario. ... Nick Swisher started at first base in Teixeira's place, with McGehee expected to arrive Wednesday. ... Reliever Joba Chamberlain was initially scheduled for another rehab appearance for Class AA Trenton on Tuesday, but he was told to report to the Yankees after they traded Qualls. Chamberlain arrived at Yankee Stadium at 5:30 p.m., Girardi said. He didn't pitch Tuesday, but he would be available to pitch two innings Wednesday, according to Girardi. Chamberlain severely injured his right ankle this spring while rehabbing from Tommy John surgery. ... Orioles DH Jim Thome was placed on the 15-day disabled list with a herniated neck disk, the team announced. Infielder Robert Andino was activated from the DL to replace Thome. ... Despite several reports the Orioles were close to a deal for Philadelphia Phillies righty Joe Blanton (8-9, 4.59 ERA), Baltimore stood pat as the trade deadline passed. General manager Dan Duquette told reporters he would have liked to have made a deal, but he felt the club had better options than the players it was offered.