Nate Schierholtz went 2-for-5 in his Phillies debut.
Jimmy Rollins tied the game with a solo shot to lead off the fifth inning at Nationals Park, and Schierholtz made it back-to-back home runs to give the Phillies a 3-2 lead.
The final score: Phillies 3, Nationals 2.
Stay in the game with the latest updates on your beloved Bay Area and California sports teams! Sign up here for our All Access Daily newsletter.
The Giants traded Schierholtz to Philadelphia on Tuesday for two-time All-Star Hunter Pence.
Schierholtz appeared in 503 games for the Giants from 2007 to 2012, batting .270 with 23 home runs and 119 RBI.
He was drafted by the Giants in the second round of the 2003 MLB Draft.