Oakland rookie Tim Birtsas was constantly fighting his excitement this afternoon, and probably wasn't as effective at that as he was at shutting down the Baltimore Orioles in his first major league start.

Birtsas, 24, allowed five hits over six innings and gave up only one legitimate run as the A's beat the Orioles, 4-2, at the Oakland-Alameda County Coliseum.

"I was overly excited," Birtsas admitted. "I had to keep myself calm. I thought overnight about what I'd do against each hitter, but it's a lot different getting out here to do it today."

Baltimore rookie Ken Dixon, who is a month younger than Birtsas, also allowed only five hits in six innings. But in the sixth he got a pitch out over the plate to Dave Kingman, who sent it back up the middle for a base hit that scored Alvin Davis, who had doubled with two out.

"Kingman got the big blow," said Dixon (4-2). "If I get that pitch down, he doesn't place that ball like he did."

That gave the A's a 3-2 lead, and they added a scratch run in the eighth with a single, two stolen bases, an error and a walk off reliever Sammy Stewart.

The three-game series, which the A's won, 2-1, was a pitcher's delight. Neither team scored more than four runs in any one game. And everyone, from today's 24-year-old rookies to Wednesday night's 40-year-old loser Don Sutton, was very effective.

In fact, none of today's runs resulted from a show of power. As Dixon said, "They didn't exactly hit me real hard."

If each pitcher had gotten better defensive support, the game might have gone into extra innings tied, 1-1, because only two of the runs were anything to brag about.

The Orioles took a 1-0 lead in the second when Eddie Murray's grounder to short rolled under the glove of Alfredo Griffin, who easily could have been charged with an error.

On the following play -- Gary Roenicke's grounder to short -- Griffin fielded the roller but threw it five feet over the first baseman's head, and it bounced into the stands. Murray, who had already gone to second on a wild pitch, scored Baltimore's first run.

Fritz Connally's single made the run earned, but Birtsas got Rich Dauer to ground into a double play to end the inning.

Oakland came back with two runs in the fifth. Dusty Baker singled to left, only the second hit given up by Dixon. Dwayne Murphy's pop fly would have gone into the stands on a normal day, but the wind blew it back into play and it dropped just inside the left field line, 100 feet behind third base among three Baltimore fielders.

Baker should have been dead at third, but Dixon couldn't handle the throw from shortstop Cal Ripken. "I was playing for the hop, but it didn't hop at all," said Dixon, hinting that he thought he should have received an error on the play. "The throw was right in there."

Mickey Tettleton's grounder to short scored Baker, tying the game at 1. The A's manufactured the lead run when Donnie Hill executed a suicide squeeze on a 1-2 count.

The Orioles were thinking along those lines. On a two-strike pitch, catcher Rick Dempsey had Dixon throw a pitchout, but Murphy didn't move. On the next pitch, which seemed to be high and slightly outside -- a good pitch to bunt -- Hill put it down right in front of the plate and Murphy scored standing up for the 2-1 Oakland lead.

Baltimore tied it at 2 in the sixth when Ripken walked and scored on Roenicke's double to left.

Kingman's single in the sixth put Oakland ahead for good. The A's run in the eighth was almost comedic. Dave Collins walked and stole second after Stewart, on a prior pitch, turned the wrong way -- toward second base -- in throwing to first.

On ball four to Carney Lansford, Collins stole third, colliding with third baseman Wayne Gross. The ball rolled back toward the mound and Collins came home with Oakland's final run.

Gross had to leave the field and needed stitches in his forehead.

The Orioles had to be impressed with Birtsas, who is 6 feet 7 and throws like it. The left-hander retired Fred Lynn four times with runners on second base.

Birtsas got late help from Keith Atherton and Jay Howell, who earned his 10th save.