Ken Singleton's three-run homer highlighted a five-run first inning that gave the Baltimore Orioles an 8-2 victory over the Mariners today.

Twice Eddie Murray of the Orioles drove in two runs with singles.

Al Bumbry started the game with a single off Gaylord Perry (2-3). After Dan Ford forced Bumbry, Cal Ripken doubled and Murray singled to score two runs. John Lowenstein walked, then Singleton, batting left-handed, homered to left. It was his 12th homer in the Kingdome; no other visiting player has hit more.

Lowenstein homered off Perry in the third inning and Murray ended the Orioles' scoring with a two-run single in the ninth. Perry has yielded 10 home runs in 34 innings this year.

Storm Davis (1-0) started for Baltimore in place of Jim Palmer and allowed four hits in 5 1/3 innings. Tippy Martinez finished for the Orioles and earned his second save.

Palmer said his back is sore, as it has been since late March.

Seattle scored in the second inning on Pat Putnam's double and Ken Phelps' single. Rick Sweet homered in the fifth for the other run.

Singleton was two for three today and raised his average 60 points in the three-game series here.

Seattle Manager Rene Lachemann said he was concerned about Perry's plague of opposing home runs this season and a decision to change his pitching status may come out of a conference he planned with Perry, owner George Argyros and Dan O'Brien, the club president.

"He was trying to get the ball in on Ken Singleton and got it out over the plate," Lachemann said.

Davis, meanwhile, remarked on his status as the utility man of the Baltimore Orioles pitching staff. "One of the things I'm here to do is fill in," he said. "That's one of my jobs."

Davis said he learned after Saturday night's game that he would be subbing for Palmer today.

"I would really like to know a couple days ahead of time," he said.

Davis, however, made the most of his opportunity. He has been troubled by a sore finger. He split a knuckle throwing his curve ball about 10 days ago. Consequently, he stuck with his fast ball.

"I was pretty strong, almost too strong," he said.