Wei-Yin Chen was so good in his previous two starts that seeing the Baltimore lefty struggle to finish four innings and get battered by Seattle was surprising.

"I thought he was pretty crisp with his fastball as evidenced by his strikeouts. He made a lot of mistakes with his off-speed pitches," Orioles manager Buck Showalter said. "That is usually not indicative of him (and) he paid a price for it."

Michael Morse hit an opposite-field two-run homer, his third shot in four games, Aaron Harang pitched six solid innings for his first victory, and the Mariners won their second straight series by beating the Orioles 8-3 on Wednesday night.

After not winning a series for most of April, the Mariners went 5-2 on their homestand, taking three of four from the Angels and two of three from Baltimore.

Morse's homer was the highlight on a night when the Mariners scored four times with two outs off Chen (2-3). Michael Saunders had three hits and scored three times, and Kendrys Morales had three RBIs, including a two-run double in the sixth inning.

"I just tried to make a pitch, but I couldn't make it stay in and it cost us," Chen said through an interpreter. "I didn't give our guys a chance to win the game."

That feeling of making mistakes wasn't isolated to Chen. Center fielder Adam Jones also felt that way after misplaying a deep fly ball in the second inning that went for a triple by slow-footed catcher Jesus Montero and eventually led to two runs for Seattle. Jones also had two other sinking liners come his way that he couldn't catch.

"I missed it and it cost my team what turned out to be a pretty big inning," Jones said. "I need to clean ... up defensively. It's ... frustrating."

Morse became the first Seattle hitter to have nine homers in the team's first 30 games since Mike Cameron in 2002. Cameron's total included a four-homer game, and Morse was slowed in April by a small fracture in the little finger on his right hand.

Seattle was hitting just .230 on the season with two outs, but scored four runs on key two-out hits. Bay got the Mariners started with a double into the left-field corner to score Morales in the first after Chen easily got the first two outs of the game.