Ryan Zimmerman's pinch-hit RBI single in 3 victory over the Phillies in the first game of a doubleheader on Tuesday.
Michael Morse drew a two-out walk in the 10th and Michael Stutes (6-2) intentionally walked Danny Espinosa before Zimmerman looped a single into center field. Morse slid ahead of a wide throw for the go-ahead run.
"He likes those situations," Nationals manager Davey Johnson said of using Zimmerman as a pinch-hitter.
The doubleheader kicks off a four-game series between the division rivals.
The NL East-champion Phillies, after capturing their fifth division crown in a row over the weekend, continued using a patchwork lineup in the Tuesday afternoon's opener.
But manager Charlie Manuel has a plan to get back to normal by the end of this weekend's series against the Mets.
"I'll start really playing our regulars the last two games in New York," Manuel said. "I'd like to get our lineup set and let them play a little bit before [the playoffs]."
Phillies right-hander Kyle Kendrick and Nationals lefty Tom Milone both allowed just four hits in nearly identical six-inning starts. Kendrick struck out four, Milone fanned two and neither pitched walked a batter.
The Phillies fell to 4-7 in their last 11 games, while the Nationals improved to 7-2 in their last nine. Washington has won five straight road games for first time since May 31-June 5, 2006.
Washington jumped on Michael Schwimer in the seventh and took the lead on Bernadina's three-run homer.
The blast, which reached the facing above the upper deck in right field, came after Steve Lombardozzi was called out on a close play at home plate.
Lombardozzi singled and went to third on Alex Cora's base hit, then charged home on Ian Desmond's bunt to the first base side. Catcher Erik Kratz, in his Phillies debut, scrambled for the ball and dove back to tag the sliding Lombardozzi on the leg.
Replays showed the tag may have been a little late. Three pitches later, Bernadina cranked a fastball for his seventh homer of the season and a 3-0 lead.
"I was looking for a pitch, fastball in, and he left it over the middle of the plate," Bernadina said.
Philadelphia tied the game against in the bottom of the inning on Ibanez's pinch-hit homer.
Manuel countered with the lefty Ibanez, who lined an 0-2 fastball into the right field stands for his 20th homer and a 3-3 game.
The Nationals stranded a runner in scoring position in the ninth after Desmond singled and stole second, while the Phillies had men at first and second with one out and couldn't get anyone home in the bottom of the inning.
That was a running theme earlier in the game.
The Phillies stranded two runners in the first inning, and one apiece in the second and fifth. Tha Nationals left the bases loaded in the third when Rick Ankiel grounded out. They stranded a runner at second base in the fourth, and left runners at the corners in the sixth.
Cliff Lee is pitching Game 2 for the Phillies, while Ross Detwiler is starting for the Nationals...Phillies left-hander Joe Savery made his MLB debut in the eighth inning, giving up a single and getting one out...In a play for the highlight reel, Kratz bare-handed a Bernadina foul tip for strike three in the first inning, snaring the ball out of the air after it deflected off the top of his glove...The Nationals have won each of Milone's first four MLB outings.