Kurt Suzuki and Brian Dozier went deep for the Nationals.
Bryce Harper was 0 for 3 with a walk in his third game against his former team but helped prevent a run with a perfect relay throw.
Phillies right-hander Vince Velasquez allowed two runs and four hits in five innings in his first start this season. Seranthony Dominguez (1-0) tossed a perfect sixth, Adam Morgan and David Robertson each tossed scoreless innings.
Pat Neshek pitched out of trouble in the ninth for his first save.
Dozier led off the inning with a homer to cut the deficit to 4-3. Anthony Rendon followed with a double. But left fielder Andrew McCutchen ran down Juan Soto’s drive to left, Ryan Zimmerman grounded out to second and Suzuki flied out to right.
Anibal Sanchez (0-1) gave up three runs and seven hits in 5 2/3 innings in his second start against Philadelphia in five days.
Hoskins, who hit a two-run homer a 2-1 win over Minnesota on Sunday, gave the Phillies a 3-2 lead in the sixth on his fourth homer. He took Justin Miller deep in the eighth to make it 4-2.
After circling the bases both times, Hoskins did a series of choreographed handshakes with several teammates.
Washington took a 2-0 lead in the second after Soto lined a double and Suzuki ripped a homer to left.
The Phillies tied it in the fourth when J.T. Realmuto hit a single and Herrera followed with a drive to the seats in right-center.
Zimmerman was thrown out trying to score from first base on Suzuki’s hit in the fourth when Harper chased the ball down in right-center and quickly fired to shortstop Jean Segura, who threw a strike to catcher Realmuto.
Dozier homered in the ninth against Neshek. It’s his first homer since signing a $9 million, one-year free agent deal. He totaled 76 homers between 2016-17 before disappointing last season with Minnesota and the Dodgers.
Sanchez has made four straight starts against Philadelphia going back to his final two outings with the Braves last season. He’s 5-10 career vs. the Phillies.
Nationals: OF Michael Taylor (right knee/hip sprain) was activated from the 10-day injured list. OF Andrew Stevenson was optioned to Triple-A Fresno.
Phillies: OF Roman Quinn (right oblique strain) will continue his rehab work in the minors, though the team hasn’t decided whether he will move up to face tougher competition.
RHP Aaron Nola (1-0, 7.00 ERA) goes for the Phillies and RHP Stephen Strasburg (1-0, 2.84) starts for the Nationals in a matchup of aces Tuesday night. Nola, who finished third in NL Cy Young award voting last year, got roughed up in Washington last week, allowing six runs in three innings.