The first place Baltimore Orioles, leaving tonight on a nine-game road trip, gave their burgeoning band of fans something to remember with a three-run ninth-inning rally that disarmed the Texas Rangers, 5-4, today.

Although they lost shortstop Mark Belanger with a broken finger, the Orioles had many memorable moments, including a triple play and back-to-back home runs by Benny Ayala, his first two for the Orioles. But that was all window dressing for what took place in the last half of the ninth.

Eddie Murray, batting right-handed, hit an opposite - field fly ball for his 12th double. Lefty Jon Matlack then departed, replaced by fireballing right-hander Jim Kern, bearing a 7-0 record with nine saves.

Kern walked Gary Roenicke on four pitches and Lee May was called upon for his first sacrifice bunt since April 12, 1977. It was a good one, toward third, and it brought third baseman Buddy Bell in to field it. Kern arrived first, however, and whipped a throw toward the unguarded base, forcing umpire Durwood Merrill to leap for his life.

Murray scored, pinch runner Al Bumbry reached third and May stopped at second. Doug DeCinces was purposely walked and Pat Kelly, with a history of four straight pinch hits, batted for Rich Dauer and grounded into a double play, Bumbry scoring the tying run.

Another pinch hitter, John Lowenstein, was intentionally walked, but Baltimore brought up yet another lefty swinger, Terry Crowley, to bat for Kiko Garcia. Crowley blasted a 2-2 pitch into deep right-center, beyond the reach of either outfielder, and the whole Baltimore team gathered at the pitcher's mound to celebrate its fifth straight victory.

"I've hit the ball just as well the last few times, but nothing would drop," Crowley said. "I could see this one was going dead between the outfielders, but I was sure happy to see it touch the ground. That guy was throwing at 94 or 95 miles an hour and probably nobody else in the league throws that hard, so I was dead looking for a fast ball and I got it."

Right-hander Dennis Martinez went the distance for Baltimore to record his ninth straight victory. He was struggling much of the way as his curve repeatedly missed the strike zone, but he hung on for his first decision against a Texas team that has given him nothing but trouble.

The triple play was, of course, most helpful. It came in the sixth inning with Texas leading, 3-1, Al Oliver on second and Pat Putnam on first. Bell lashed a hit-and-run line drive at third baseman DeCinces, who landed on third base after he caught it and probably could have made both tags himself. Instead, he made a leisurely throw to second to Dauer, who made an equally leisurely toss to Murray at first.

"A line drive is a lot easier to turn into a triple play than a ground ball," said DeCinces, who was involved in an around-the-horn grounder type a year ago. "I don't think this ball would have landed fair anyway, but it sure helped us out.

"I turned around and knew Al was right there, so my first thought was where the runner on first was. Then I saw Putnam and I knew I had all day."

Until the ninth, Ayala was the Orioles' offense, with home runs in the fourth and sixth innings. He was obtained from St. Louis in January for minor leaguer Mike Dimmel and has no illusions about a World Series check.

"I figured they just made the trade so I could help out in Triple-A at Rochester," Ayala sais.

Ayala, 28, had hit three home runs for the Mets during brief major league trials and was familiar with former Met Matlack's offerings.

"He used to throw his high pitch a lot harder," Ayala said. "It wasn't that hard today and I got on it."

A 22,658 gate brought the weekend total to 101,003 and put the Orioles 114,492 ahead of the 1978 pace.

Every bright day has its sunburn, however, and in the euphoria that gripped their dressing room the Orioles were not forgetting Belanger, who fractured the middle finger on his right hand while fielding Bell's grounder in the second inning. Belanger will be lost for three weeks.

"They may have to put a pin in it," Belanger said. "I put may hand in the glove (pocket) before the ball got there. If I was a one-handed fielder, it wouldn't have happened."

To replace Belanger, the Orioles recalled Wayne Krenchicki from Rochester.