On May 20, 2006 — In interleague play, Josh Beckett hits a solo home run, picks up an RBI single, and pitches seven solid innings to lead the Boston Red Sox over the Philadelphia Phillies, 8 – 4, at Citizens Bank Park. Because the designated hitter isn’t used in National League parks during interleague play, regular Red Sox DH David Ortiz starts at first base. Beckett posts his third straight win and gives the AL East-leading Boston its 10th victory in 13 games. He also becomes the first Red Sox pitcher to hit a home run since Marty Pattin on September 26, 1972.

Source:
Baseball Reference May 20