The fast-fading Baltimore Orioles are in trouble. One-half game out of first place just more than a week ago, they dropped 4 1/2 games behind the resurgent New York Yankees today by losing their third game in four days to the gritty Oakland A's.

This time it was Oakland starter -- and of course finisher -- Steve McCatty who pitched the complete game that stopped the Orioles, 5-2, and made bleak the Bird's hopes of defending their American League Championship title in October. With less than a month to play down the pennant stretch, the Yankees -- winners today over woeful California -- are in command in the East division.

"Before all the talk about the race being over starts." pleaded Oriole Manager Earl Weaver, "let me tell you that on July 18 when we started the surge, we would have been more than happpy to settle for four games down in the loss column now."

But even Weaver, the eternal strategist and optimist who has always done well in September, had to backtrack on that statement.

"But with 27 games to go, it's getting a little scary, I'll admit. There ain't no margin for error now."

For the fourth straight game againstBilly Martin's West Coast spoilers, the Orioles played far less than championship-caliber baseball, making two errors and stranding runners when they did manage to get them.

McCatty (11-3) allowed only six hits in pitching his eighth complete games, which permitted Oakland's pitching staff to set a major league record for complete games (78), breaking the old mark by the 1968 San Francisco Giant staff.

"All I've got to say is the record is now in the American League where it should have been all the time," Martin said.

His A's bunted the Orioles into submission this weekend with seven bunt singles and countless more sacrifice bunts and suicide squeeze attempts.

During one stretch in the fourth inning today when they scored two runs, Jeff Newman, Dave McKay and Rob Picciolo bunted successively -- each perfectly. One went for a base hit, another for a sacrifice and the third for a run-scoring suicide squeeze, Oakland's 14th in 21 tries this year.

Oakland had already taken a 3-0 lead off loser Steve Stone (22-6) in the first inning. Rickey Henderson walked (he leads the leaue with 96) and stole his 72nd base -- his eighth in nine attempts this year against the Birds. Dwayne Murphy followed with a run-scoring single and Dave Revering's double and Wayne Gross' run-scoring hit were all McCatty needed.

"The Cat" encountered just one sticky situation. In the third inning Baltimore scored both its runs on base hits by Kiko Garcia and Al Bumbry, a walk to Rich Dauer, an error and a sacrifice fly by Eddie Murray. That was the entire Oriole offense for the afternoon.

McCatty allowed only three hits in the last six innings and Stone retired the last 12 Oakland hitters in a row.

"McCatty was over 90 mph in the first few innings and then he slowed down" Weaver said. "We thought we had him then, but some guys get run down a bit and get you out on control and savvy."

In 34 innings pitched by Oakland starting pitcher in this four-game series, Oriole hitters managed just seven runs and 21 hits.

"We should have swept them all four,"said Revering, who had an RBI double and a single today. "We just gave them that game the other night."

Now the Orioles must go on a six-dayroad trip and face Toronto and another strong pitching staff in Detroit.

"We still feel we're in it; the change of scenery may do some good," said Baltimore pitching coach Ray Miller after his pitchers were outdone in the head-to-head competition between the best two staffs in the major leagues.

"I've never seen Baltimore play this sloppy in my three years in the league," Revering said. "They drop another game and they're in trouble. Real trouble."