When the black cat dashed into the Baltimore dugout, the Orioles were in a good mood. Rich Dauer had just hit their fourth home run of the night off Milwaukee Brewers' pitching; a symbolic 6-4 Baltimore victory over their AL East arch rivals was in the offing and the Orioles were a bit giddy.

Benny Ayala, who, like Eddie Murray and Gary Roenicke, had already lofted balls over the left field fence off southpaw Mike Caldwell, decided that a black cat's tail was just what he wanted as a souvenir of the evening. Naturally, John Lowenstein wished to oblige.

"I figured I'd just kill it with my bat and give that tail to Benny," said Lowenstein, known for telling what Mark Twain might have called a stretcher.

When Lowenstein's bat smashed the concrete dugout steps an inch from the feline's tail, Memorial Stadium was provided with the first rocket-launched cat. The animal did just what the Orioles hoped it would. The thing ran for its life directly through the middle of the Milwaukee infield, perfectly splitting the distance between the mound and plate before continuing its dash through an opening in the right field fence.

For the Orioles, it was the perfect exclamation point at the end of a night of Baltimore explosions. The first-place Orioles reintroduced the Brewers to the unfriendly confines of Memorial Stadium this evening with long balls, black cats and pitchers named Martinez--Dennis, who won, and Tippy, who saved.

For the Orioles, who have won five of six and eight of 11 since their seven-game losing streak, this night had only one disappointment. Where were all those home runs the last time these two teams met--on Oct. 3, 1982--when a division pennant and an entire season was at stake? Baltimore has beaten Milwaukee in six of their last seven meetings, but the one that mattered most escaped. Now, the best that the Orioles can do is settle for a new start.

"We could have had seven or eight home runs tonight," said Cal Ripken Sr., Orioles third base coach. "I'm not sure I've ever seen a team hit so many long balls in one game in this park."

From the moment that the first Baltimore batter, John Shelby, hit a ball to the top of the fence in center field, where new Brewer Rick Manning made a leaping catch, this evening's tone was set. Before that first inning was over, Murray and Roenicke had homered on consecutive pitches to put the Orioles, who have a two-game lead on second-place Toronto, ahead to stay.

Were it not for Ben Oglivie, who leaped above the left field fence to rob Murray of a second homer and who made a tumbling sliding catch to take an RBI double from Shelby, the Brewers' deficit might have been greater.

"I thought Earl Weaver sent the cat," said Milwaukee's Don Sutton.

Because of Dennis Martinez, this Baltimore victory seldom seemed in doubt. He gave up tainted single runs in the first and fourth, in large part because Dauer and Roenicke played a pair of semitough line drives into hits. And he grooved the first pitch after an error by Cal Ripken Jr. in the seventh, allowing No. 9 hitter Ned Yost to hit a first-row homer. But, for the most part, the 4-9 righty had his best night of the season, working 7 1/3 innings, walking no one and beating the Brewers for the fifth straight time.

As confident as Martinez seems against the Brewers, tailing his fast ball off edges of the plate and watching the slug-happy Brew Crew chase them, that's how helpless the speed-changing Caldwell seems against the Orioles, who've beaten him eight straight times. "We just ignore his fast ball and sit on (wait for) his sinker and changeup," said Dan Ford. "There's almost nobody in our lineup that he can throw a fast ball past."

Certainly not Roenicke or Ayala, who are 16 for 32 and 10 for 20 off Caldwell in their careers. As for Murray, he doesn't care who's pitching; after going 31 games without a homer, he's hit six homers in 11 games with 14 RBI. Caldwell even helped Dauer (.201) get out of a one-for-25 slump. After a single off Caldwell, Dauer hit a homer into the first row of seats in left off reliever Bob Gibson. It was the first RBI for Dauer since May 6.

Dauer's homer gave the Orioles a 6-4 margin, which Tippy Martinez protected for the last five outs. Martinez, who has permitted just three of 24 inherited runners to score this year, struck out Ted Simmons and got Oglivie to fly out with a man on to end the eighth. Then, in the ninth, Martinez walked the first two batters; "I don't know what Tippy was trying to do in the ninth," growled Manager Joe Altobelli.

Martinez rediscovered control of his curve and struck out Yost. Paul Molitor lined out solidly to left and Don Money grounded out weakly.

This game, in which the Orioles hit four homers for the first time this year and the Brewers allowed four for the first time, capsulized the moods of these teams. The Brewers (26-25) seem flat after learning on Monday that Rollie Fingers will be lost for the year due to arm surgery and that team leader Gorman Thomas was traded to Cleveland for Manning, who arrived this evening and went zero for four, snapping his uncharacteristic 17-game hitting streak.

The Orioles, however, were heartened to learn that Jim Palmer expects to start a game next week in Milwaukee. Until his return, the Orioles only expect to be forced to use one more bizarre emergency starter--Allan Ramirez, just up from Rochester as Don Welchel was sent down--who will start against Sutton Wednesday.