Oriole pitcher Dennis Martinez, backed by home runs by Eddie Murray and Gary Roenicke, notched his 11th complete game in 22 starts today, stopping the Oakland A's on a seven-hitter in a 3-1 Baltimore victory.

The victory halted a four-game losing streak for Martinez, whose last win came on June 20 against Cleveland.

The Orioles lost a scoring opportunity to overeagerness in the second.

John Lowenstein, who homered and singled in his last two at-bats Tuesday night, singled to lead off the inning. Doug DeCinces walked and Gary Roenicke sent Rickey Henderson sprinting to the warning track in deep center to haul down a line drive that moved Lowenstein to third.

But with a 2-1 count on Billy Smith, Lowenstein wandered a step too far from third base and was picked off by catcher Jim Essian. Smith's high fly deep to right came one pitch too late.

The Orioles scored a charity run in the fourth inning. Murray hit a high, leisurely pop fly to shallow left field that shortstop Rob Picciolo and out-fielder Mike Heath politely watched fall at their feet for a double. After Murray took third on Lowenstein's groundout, DeCinces singled cleanly to left to score the game's first run, and then was caught trying to steal, for the third out.

The Birds barely missed another freebie in the fifth, when an error, a walk and a fielder's choice put men on first and third with two outs. Kiko Garcia sent a drive shrieking to the wall in straightaway center, but the A's Henderson made a shoulder-crashing catch to end the threat.

In the bottom of the fifth, the A's loaded the bases against Martinez but AlBumbry's catch of Wayne Gross' deep liner and Dave Skaggs' tag of Henderson trying to score from third kept the A's scoreless.

In the sixth, Murray hit a fly ball to right that fell just over the fence for his 10th home run, making the score 2-0.

Roenicke made it a 3-0 game when he led off the seventh by plowing Steve McCatty's second pitch some 20 rows into the left field seats for his 15th home run of the season and his fifth of the year off A's pitching.

In the A's half of the seventh, Henderson spiked Murray while beating out a leadoff infield hit. Martinez was allowed to continue throwing from the mound while Murray went to the dugout for repairs, sparing Earl Weaver another ejection by the umpiring crew, which waved him off the field after a protest in similar circumstances last night.

Dave Chalk then singled, and a wild pitch moved up Henderson and Chalk. Henderson scored on Mitch Page's groundout, but the A's could work no more out of Martinez. CAPTION: Picture, Dennis Martinez