The win moves the Yankees one-half game ahead of the Orioles in the American League Wild Card standings. With the Indians' 10-5 loss to the Tigers on Saturday night, New York gained sole possession of third place in the race for the final two playoff spots, leaving the Yankees looking up at just the A's and the Rays in the standings.
"It sure beats four and five, which is what we were looking at," manager Joe Girardi said. "We've got to keep winning. You can't rest on what you've done. You've got to keep winning."
Nova needed only 104 pitches to get through those nine innings, giving up just three hits and striking out five in his first career shutout.
"Unbelievable. It's unbelievable," Nova said. "I feel really good, because I'm giving my team a chance to win every time I go out there."
Baltimore wasn't able to get anything going against Nova throughout the game. Only six batters reached base against him, and the Orioles only advanced one baserunner past first base.
The Orioles have now been the victims in both of Nova's complete-game efforts this season, as the right-hander allowed just two runs over nine innings against them in a July 5 win.
"He has a power curve. Didn't make many mistakes up with it at all. Stayed in the strike zone a long time, then left the strike zone," Orioles manager Buck Showalter said. "It's very easy to sit in the dugout or the stands and say, 'Why aren't we doing [more]?' The guy's got a 2.9-something ERA in the American League East. It's impressive."
The Yankees staked Nova to an early lead, as center fielder Brett Gardner doubled to lead off the first inning and second baseman Robinson Cano hit a double of his own to drive Gardner in and put New York on top
The first-inning run was the only blemish for Orioles starter Scott Feldman, who allowed six hits and one walk while striking out five over seven innings.
The one-run lead held until the eighth inning, when Cano gave the Yankees some insurance and crushed his 25th home run of the year into the right-field seats.
The Yankees' second baseman will be sad to see the calendar turn to September on Sunday, as he hit .370 in August, his highest batting average in any month this season.
"You could see early in the season everything was away and they made me chase pitches," Cano said. "Now it's a big difference. [Alfonso] Soriano has, what, 12 home runs and  RBIs [as a Yankee]? That's the last guy you want to face."
Girardi sent Nova out to pitch the ninth inning with a two-run lead, and left him in there to face the heart of the Baltimore lineup after left fielder Nate McLouth singled on a hard shot right at the pitcher.
"There wasn't anything that I didn't like. Everything that I kept seeing was positive, positive, positive," Girardi said. "I liked what he had done in the middle of their order, all day."
"The confidence that [Girardi] has in me is unbelievable," Nova said.
But after third baseman Manny Machado flied out to left for the first out in the ninth, Chris Davis gave the Yankees a scare. The power-hitting first baseman, and Major League home run leader, lifted a fly ball deep to right field, taking Ichiro Suzuki all the way to the warning track.
Ichiro paused about two feet from the wall and looked as though he was preparing to jump to try to keep the ball in the ballpark. He wouldn't have to, though, as what looked like the potential game-tying home run dropped right into his glove on the warning track.
"Anytime a guy gets a ball in the air, you always hold your breath. Especially here, in that part of the park, anything can go out," catcher Chris Stewart said. "He didn't get enough of it, the ball stayed in the yard, and that's a big play for us."
Asked if he knew he was going to catch the ball off Davis' bat, Ichiro said, "Absolutely."
"I was just having fun," Ichiro said. "The result is the most important. If you look like you're going to get it and it goes over the fence, obviously the fans wouldn't be excited about it. But if the fans thought 'Oh, no,' then you make the play -- humans want to come from a bad place to a good place."