Baltimore's Dennis Martinez extended his mysterious 1983 tumble tonight by failing to last two innings against the previously slumping Boston Red Sox.

Tonight, those Red Sox looked like All-Stars against Martinez, who lost for the 10th time in 14 decisions. This was one of his poorest efforts, as Boston won, 5-3, before 35,403 in Memorial Stadium.

Although Sammy Stewart pitched well enough in relief once he got out of the second inning, the Orioles were left to wonder what their American League East lead would be if Martinez pitched the way he did last season, when he won 16 games. That lead now is down to 1 1/2 games over Detroit.

Despite Martinez's continuing slump, Manager Joe Altobelli said he would not move him to the bullpen.

"We really don't have any other alternatives (for starters)," Altobelli said, although Sunday he will give Jim Palmer his first start since April 26. Palmer, coming off back and arm troubles, will replace Storm Davis, who has the flu.

"Other than his last two starts (both against Boston), he really hasn't pitched that badly," Altobelli said. "You have to think that the next club that rolls in here, like the Yankees, he may crank it up. At least I can keep hoping that and run him out there."

Martinez lasted only 4 2/3 innings against the Red Sox last Sunday in Fenway Park, giving up seven hits and five runs, including four home runs. Tonight, Boston ignored the homer route and knocked out Martinez in 1 2/3 innings with the hunt-and-peck method: six singles that eventually led to four runs.

By the time Martinez had thrown his 37th pitch, a wild one past batter Dwight Evans, Altobelli had seen enough. In came Stewart, who surrendered a double to Evans for two more runs and a single to Jim Rice for another.

The Red Sox made that 5-0 lead hold up, thanks mainly to the pitching of left-hander Bob Ojeda (4-2). Keeping Baltimore offbalance with a fine changup, Ojeda gave Boston a much-needed lift with his four-hit effort over 7 2/3 innings. Despite a solo home run to Eddie Murray, Ojeda might have worked his second complete game of the season, but the last of his six walks in the eighth was one too many for Manager Ralph Houk, who went to Bob Stanley.

Stanley hardly was overpowering. In the eighth, he gave up a single to Rich Dauer to drive in Gary Roenicke, who had doubled off Ojeda. With one out in the ninth, John Shelby, Dan Ford and Cal Ripken singled for another run. Oriole fans hoped for another successful comeback, but Stanley struck out Murray on three straight pitches (Murray has a .437 lifetime average against Stanley) and then Roenicke bounced to third for the final out. It was Stanley's 13th save.

Perhaps the Red Sox won out of fear. Before the game, Houk had given them what second baseman Jerry Remy called an "old-fashioned butt chewing" to try to snap his team out of a slump in which Boston had lost nine of its last 11 games before tonight.

Said a happy Ojeda, who lost to Baltimore, 10-6, last weekend: "Ralph told us that we could either start playing some baseball out there or we'd wind up picking fruit somewhere. It wasn't much of an alternative."

Certainly, the Red Sox came out inspired. Both Remy, who went four for five, and Rice, who got the 1,500th hit of his career, singled in the first inning, but Boston couldn't score.

In the second, Carl Yastrzemski and first baseman Ed Jurak singled. Third baseman Leo Hernandez temporarily saved Martinez with a diving stop of Gary Allenson's grounder, preventing a run but loading the bases. After Glenn Hoffman flied to right to score Yaz, Remy singled under the glove of shortstop Ripken for another run. Martinez then threw the wild pitch, and quickly was out of the game, leaving to a serenade of boos from the hometown fans.

Stewart was much more effective. Boston had 11 hits through the first four innings but made only one thereafter.