WASHINGTON (Reuters) - Roy Oswalt's debut with Philadelphia was a dud as the Washington Nationals pounded the Phillies and their newly acquired pitcher 8-1 on Friday.

Oswalt, acquired by the Phillies in a trade with Houston on Thursday, allowed five runs (one unearned) on seven hits over six innings. The 32-year-old right-hander walked two and stuck out four in an 86-pitch performance at Nationals Park.

"I came out a little amped up, holding the ball a little bit tight," Oswalt told reporters. "I didn't really start feeling better until the last two innings, actually.

"It didn't really go my way."

Nyjer Morgan tripled on the first pitch from Oswalt in the first inning and scored on an RBI ground out by Adam Kennedy to put Oswalt in an early hole.

"I just basically wanted to get the party started off right, and it happened," Morgan said. "Same Oswalt. He's got electric stuff, but we just jumped on him."

The Nationals added two more in the third on a throwing error by Phillies catcher Carlos Ruiz and a sacrifice fly by Ryan Zimmerman.

In the fifth, Oswalt (6-13) surrendered a double to Kennedy and with two outs hit Adam Dunn with a pitch. Both came in to score on Josh Willingham's double.

The Nationals scored three more in the seventh inning off reliever Chad Durbin while the Phillies scored their lone run on a solo home run by Jayson Werth in the seventh.