PHILADELPHIA -- Maikel Franco got exactly the pitch he wanted, and he didn't miss it.
Franco drove the first pitch he saw from Matt Grace (0-2), a 93-mph fastball, over the wall in left. It was Franco's 15th homer of the season and second career walkoff.
"I was looking for a fastball middle-in, and as soon as I hit it I knew the ball was going to go," Franco said. "That's a great day, a great moment. It's something I can't forget."
Hector Neris (2-4), who blew the save in Philadelphia's 4-3 loss to the Nationals on Saturday, struck out the side swinging in the top of the ninth.
J.T. Realmuto also went deep for the Phillies, who avoided a three-game sweep.
After connecting, Franco immediately dropped his bat, thrust both forefingers in the air and circled the bases before being mobbed at home plate by his teammates who haven't done much winning in the last 1 1/2 months. The Phillies improved to 15-23 since leading the NL East by 3 1/2 games on May 29. They entered Sunday trailing the Braves by 8 1/2 in the division and behind both Washington and Milwaukee in the NL wild-card race.
"We needed this game so bad," Franco said.
A streaky hitter who has been jockeyed in and out of the lineup by manager Gabe Kapler, Franco is 8-for-14 with a pair of homers in his last four games.
"When he's swinging the bat well and the best version of Mikey, we can't take him out of the lineup," Kapler said. "That makes our lineup deep and dangerous."
"It was a good battle, and we'll move on and try to win the next one," Turner said. "We'll keep going and hopefully win the next 30 out of 40, or whatever the stats are."
Franco's homer was the 104th given up by a Washington pitching staff that entered having allowed the fewest long balls in the NL and second-fewest in the majors behind Tampa Bay.
Philadelphia went ahead 2-1 in the fifth on Jean Segura's two-out single to right and took a two-run lead in the sixth on Realmuto's opposite-field, leadoff shot to right.
The Nationals tied it 3-3 in the seventh against J.D. Hammer on RBI sigles by pinch-hitter Kendrick and Turner.
But Washington wouldn't get another hit, finishing the game with six straight strikeouts swinging.
Phillies starter Jake Arrieta gave up one run and four hits in five innings in his first start since disclosing he's been pitching with a bone spur in his right elbow that will require surgery in the offseason -- or sooner.
Arrieta is determined to continue pitching.
"I'm not 100 percent and I'm OK with that," he said. "I'm going to do everything I can to help the team shrink the margin."
Nationals right-hander Anibal Sanchez allowed three runs and six hits in six innings.
In addition to the homer, Realmuto extended his hitting streak to 10 straight games with an RBI single in the fourth. He's batting .400 (16-for-40) with a homer and eight RBI over the stretch.
Phillies: RHP Tommy Hunter (right forearm strain) was placed on the 10-day IL after hurting his arm Saturday night. Hunter missed the first three months of the season with a similar injury. RHP Edubray Ramos was recalled from Triple-A Lehigh Valley to replace Hunter.
Nationals: RHP Austin Voth (0-0, 5.52) will face Orioles RHP Asher Wojciechowski (0-2, 6.10) on Tuesday night in Baltimore.
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