Former first-round draft pick Matt Wieters went 3 for 4 with two RBIs to lead Baltimore.
Oswalt, acquired from Houston at the trade deadline last July, walked his first hitter in his Phillies spring debut but settled in enough to have what he felt was a productive start. Oswalt was the fifth Philadelphia starter to take the mound this spring, following Cole Hamels, Joe Blanton, Roy Halladay and Cliff Lee.
"I was pretty much just trying to locate fastballs, more than anything," Oswalt said. "I tried to stick with that and the changeup most of the day. My biggest thing, my goal every spring training, is to just get your fastball command down first, and then everything works off of that."
Like a couple of his rotation mates before him, Oswalt didn't leave the game unscathed. He gave up consecutive one-out hits in the second, including an RBI double to Brendan Harris. In all, Oswalt allowed two hits, walked one and struck out one.
"We got through the first wave," Philadelphia pitching coach Rich Dubee said. "The one thing that's been impressive is they're throwing the ball in the strike zone consistently. That's where you start. You have to start in the strike zone."
Hamels will begin the second turn through the rotation when he takes the mound Thursday in Fort Myers against the Boston Red Sox. While the Phillies prep their star-studded stable of starters, the Orioles watched promising right-hander Chris Tillman keep his arm in the race for Baltimore's No. 5 job. The 22-year-old Tillman held the Phillies to one run and three hits in two innings. He struck out one and walked one.
"It felt good to get the first one out of the way," Tillman said. "The body felt good. I was a little jumpy, a little too excited, get the ball to the plate as fast as I could. Other than that, body felt good, stuff was good - I was just a little too cute."
The 24-year-old Wieters, entering his third big league season, hit a one-out single to cap a two-run seventh that increased Baltimore's lead to 5-1. The Orioles added another run in the eighth on three of their 16 hits, 13 of which were singles.
"We swung the bats good, should have put a few more (runs) out there," manager Buck Showalter said.
NOTES: Philadelphia catcher Carlos Ruiz left the team to fly to Panama to attend the birth of his second son. Ruiz is expected to rejoin the team Friday. ... Philadelphia rookie outfielder Domonic Brown was held out against the Orioles. Brown, in competition for the starting right field job, is 0 for 12 with eight strikeouts in four Grapefruit League games. ... Orioles 1B Derrek Lee, who had offseason surgery on his right thumb, took batting practice for the fourth straight day and expects to play Saturday against Boston. ... Baltimore RHP Justin Duchscherer threw off flat ground and reported to Showalter he felt strong. Duchscherer injured his left hip last week and has yet to pitch in a game. ... The Orioles are 3-0 in exhibition games.