The victory was the 500th of manager Joe Girardi's career, and the Yankees' skipper was presented with a game ball by team captain Derek Jeter in the clubhouse.
"It's a big deal," Jeter said. "500 is like 750 in New York. He's done a great job since he's been with us, and he should be extremely proud of that."
Hughes is pitching his best ball since his 2010 All-Star campaign, having recaptured an aggressive mindset, and got through Friday's start without surrendering a home run -- something that had dented his 12 previous starts this year.
Helped by the turn of a third-inning double play that Jeter said was the key to the game, Hughes' one-run, nine-strikeout performance stifled a red-hot Washington club that had won its last six contests coming into Friday's affair.
"Good command of his fastball and expanding with a breaking ball; that's the key for him," Girardi said. "He's done a good job of it, got some strikeouts when he needed to, and for the most part, he executed his pitches."
The Yankees came in 0-12 this season in games that they had not homered, and nearly won their first with a long ball before Granderson went deep in the ninth, crushing his team-leading 20th off Tom Gorzelanny and spoiling the chances of erasing that statistical fluke.
"They mentioned that afterwards; I didn't know," said Granderson, who heard ribbing from some teammates. "I was like, 'I'm sorry, I wasn't trying to.'"
The Yankees did their most important damage in a four-run seventh inning, wearing down starter Gio Gonzalez before cracking through against Washington's bullpen.
"We didn't do much off of him," Jeter said of Gonzalez. "We were able to get his pitch count up. We had the one inning when we had some good at-bats, drew some walks. We were a little fortunate there, but that's what good pitching allows you to do. It keeps us in the game."
Brad Lidge intentionally walked the bases loaded for Jeter, who slapped a grounder to shortstop that Ian Desmond fired wildly as two runs scored.
"As many times as I made that play this year, I felt good about it," Desmond said. "It just came out a little low. Another foot and you got him. That's just the way it went tonight."
Granderson then greeted Mike Gonzalez by slapping a two-run double into the left-field corner.
"Every guy seems to be getting those opportunities during the course of the day," Granderson said. "If it's not your first at-bat, it's your second, third, fourth at-bat."
The outburst dented the final line for Gio Gonzalez (8-3), who was charged with three runs and five hits in six-plus innings. The Yankees' first runs off the lefty came on third-inning singles by Alex Rodriguez and Nick Swisher.
"The way I see it is, I was going after them, attacking them and making them put it in play," Gio Gonzalez said. "These guys were making great plays behind me, and then they just found the hole."
Hughes faced his most serious threat in the third inning, as Michael Morse's third-inning RBI single put Washington on the board. Hughes buckled down and induced Desmond to bounce to Jeter, beginning an inning-ending twin killing.
"I feel better with everything, my stuff," said Hughes, who retired nine straight through one stretch. "Aggressiveness has played a key role in that. I'm just attacking hitters. When I fall behind, [I'm] coming with my fastball instead of trying to pitch around guys, or get tentative."
Starting pitching has been the fuel for the Yankees' rush to the top of the American League East, and Hughes has loomed large in that push, coming after some wondered aloud if he should be bumped to the bullpen early this season.
Those questions have been silenced now, as Hughes has harnessed some of the advice yielded by veteran Andy Pettitte while hammering out a few points on his own.
For example, he said that he made a tweak in the third inning of his start at Detroit on June 3 that has created deception.
"It's not an overdramatic twist or anything like that; just a little turn that allows me to hide the ball better and create a better angle to home plate," Hughes said.
Whatever the fixes, the results have Hughes feeling as confident as he has been since 2010, his best summer in the big leagues.
"I feel like I'm close. Every time I go out, I want to get a little bit better," Hughes said. "We're not going to be perfect every time. That first part of 2010, I was pitching really well. I'd like to get back to that. It's a good step."