For the third consecutive evening, Baltimore pitching and defense shut down an opponent tonight as the Orioles defeated the Texas Rangers, 3-0, at Memorial Stadium.

This time, southpaw Mike Flanagan stifled the visitors on four hits in front of a hugh Tankard Night throng of 47.539.

Flanagan's gem followed a four-hitter by Dennis Martinez Wednesday against Kansas City and a two-hit masterpiece against the Royals Thursday by Sammy Stewart. The pitching could not have come to the fore at a more opportune time since the Bird bats have grown silent, producing 12 hits in the three games.

"We quit hitting after our games in Kansas City," said Oriole Manager Earle Weaver, referring to the three-game series in the final days of May.

"Then we went to Texas," continued Weaver. "We lost a couple out there, 4-2. Then on the airplane, we said that we have to get the good pitching. That's what wins you pennants.

"If we can win the 2-1 games, then go out, get some hits and win by 9-6, what more can we ask for? Anything else, and you finish at .500."

Flanagan, now 7-4 with his first win since May 12, was never in trouble. The Rangers had only six base runners all evening, and only once, in the fifth inning, did a Ranger have a teammate as company on the base paths. That one-out threat was quickly ended when Dave Roberts hit into one of two Oriole double plays.

Flanagan said the largest crowd since "Remember Brooks (Robinson) Day" in September, 1977 helped.

"The crowd was awesome," Flanagan said. "We used to go to New York and Boston and see 50,000 screaming against us. Then we'd come back here and there would be only 5-6,000 while we were trying to fight off those guys. Having nobody in the stands was a mental and moral letdown.

"Tonight they were up and screaming on my every pitch. It was a heckuva feeling."

Flanagan was successful on his sixth try for his seventh win.

"During my bad streak I'd make a good pitch, then slip up an somebody would blast it for a double," he said. "Tonight I was not trying to overpower anybody, just make good pitches and hope for some runs from the offense. I could count on my curve for a gound ball. I used the infielders a lot off my sinkers."

With the Oriole infielders in the superb form that has become a recent norm, Flanagan was in better hands than had he been covered by All-State.

Third baseman Doug DeCinces and second baseman Rich Dauer contributed two fine plays. DeCinces made a barehanded, charging snag of Billy Sample's three-hopper in the fourth and threw out the fleet Ranger for the first out. In the seventh, Dauer erased the word "hit" from Gary Holle's hot grounder with a falling, backhanded grab and a one-hop toss to first baseman Eddie Murray that nipped Holle by millimeters.

Baltimore got its runs in the fifth, courtesy of momentary wildness by Ranger starter Doyle Alexander, who otherwise limited Baltimore four hits in eight-plus innings.

Gary Roenicke singled with one our, Murray drew a walk and Dauer singled to center to score Roenicke. Alexander then walked Kiko Garcia and Dave Skaggs in succession to score Murray. Al Bumbry ended the run production by sacrificing home Dauer. CAPTION: Picture, Rich Dauer scores in fifth inning on sacrifice fly to left as Rangers' Jim Sundberg looks for ball thrown by Bill Sample. AP