Scott McGregor, the ace of the Baltimore Orioles' staff, increased his record to 13-4 tonight, shakily shutting down the Texas Rangers, 7-4.

McGregor's fifth straight victory was the Orioles' fourth straight. They lead Detroit by a half-game in the American League East.

"It's a fair streak," Manager Joe Altobelli of the Orioles said. "Four in a row is just a streak. Now, 10 or 12, you then add the 'ing.' That's 'streaking.' "

Altobelli knows that the young McGregor was called Cy Future. Tonight, McGregor became the American League's second 13-game winner and is an early candidate for the Cy Young Award.

Dave McNally, the Orioles' frequent 20-game winner of a decade ago, once told McGregor not to win 20 games, "because they'll always expect it from you."

"It's true, people do expect you to always win 20," a subdued McGregor, a 20-game winner in 1980, said tonight. "They expect you to always throw shutouts or win one-run games. But that's not even logical.

"I've had a good stretch (games of 8 2/3, 9, 9, and 9 innings pitched). Tonight was a battle."

McGregor's battle was exacerbated by Dave Hostetler's two home runs, the second giving the Rangers a 4-3 lead in the seventh. Both home runs came off fast balls that weren't.

But the Orioles didn't let McGregor's mistakes last long, as they got four runs in the seventh off rookie Mike Smithson.

Cal Ripken opened the inning with an infield single. Eddie Murray followed with a sinking liner to left, a ball that left fielder Billy Sample lost in the lights and misplayed into a triple.

"I made good pitches to both Ripken and Murray," said a chagrined Smithson. "I did what I could."

John Lowenstein drove in the winning run off Smithson (6-10) with a sacrifice fly to center. Ken Singleton followed with his third hit of the night, a single to center. Smithson was replaced.

Catcher Joe Nolan popped a double to right center off John Butcher, scoring Singleton. An Al Bumbry single made it 7-4.

The Orioles also came from behind in the third inning when consecutive singles by Rich Dauer, Bumbry, and Jim Dwyer (now hitting .333) loaded the bases for Ripken and Murray,

Each hit a sacrifice fly to tie the game at 2. Smithson, rather than seizing the moment, wilted, walking Lowenstein on four straight pitches. Singleton, who was hitting .306 with men in scoring position, singled up the middle giving the Orioles a 3-2 lead.

The Rangers had scored once in the second after Bill Stein doubled with two outs and George Wright, hitting only .209 right-handed, singled to center. Hostetler, who hit 22 home runs as a rookie last year, hit McGregor's first pitch in the third over the 405-foot sign in center.

McGregor, who's 5-0 against the Rangers in his career, needed superlative defensive plays in the fifth (by Dauer) and sixth (by Todd Cruz) to keep himself in the game.

In the sixth, Bucky Dent singled down the third base line. An aggressive runner would have made second, but Dent stayed at first. Larry Parrish, a .360 lifetime hitter against Baltimore, hit a line drive to Cruz, who leaped to his right and speared the ball.

"I saw it as soon as it left the bat," said third baseman Cruz. "I didn't know whether I was going to get it. (Afterward) I felt like I was on top of the world. The fans just kept cheering. It made me feel really good."

In the fifth, Dauer scooped up Sample's grounder, tagged Jim Sundberg and threw Sample out at first for the double play.

The frustrated Rangers, 5-18 since the All-Star break, and losers of five straight games, were occasionally teeing off on McGregor's tantalizing curves and fast balls. Only Hostetler, whose two-run homer in the seventh gave the Rangers their last lead, really had McGregor in his sights.