It would be easy to lose track of the thread of lingering meaning that ran through the 5-1 Baltimore Oriole victory over Oakland tonight in Memorial Stadium -- their sixth consecutive triumph, good for first place in the American League East.

It would be easy to forget that, within the last two weeks, Scott McGregor -- the 20-win left-hander the Birds call Cy Future -- has finally acquired the only thing he lacked: charisma. Before Baltimore's eyes, McGregor is blossoming in confidence, in game presence, in audacity. In short, he is turning from a very good pitcher into one of the game's current greats.

Despite perhaps the most artistic victory of his career -- a three-hitter in which he faced only 29 men, struck out seven and made every Oakland hitter except Rickey Henderson look completely helpless -- it would be tempting to overlook the final bursting forth of McGregor.

How could this be possible? What could overshadow McGregor's defiant changing of speeds, the way he bamboozled the A's with his knee-high changeups ("the invisible ball"), then sawed the bats of in their hands with his sneaky fast balls up and in? What could surpass a pitcher with a barely better than high school fast ball who is such a master of deceit that he may yet become the Birds' fourth Cy Young winner?

Well, try these happenings on for size:

Eddie Murray was ejected for cursing umpire Durwood Merrill in the third inning. It was such a swift and unexpected thumb that it took the crowd of 23,428 several minutes to realize what had happened.

Earl Weaver was also ejected just moments later for (pick one): covering home plate with dirt (twice), trying to throw his hat into the A's dugout, trying to berate Merrill worse than Murray already had.

"Durwood committed the one cardinal sin of umpiring," said Weaver afterward, like a principal reading out a schoolboy. "He got mad at something (the O's bench jockeying) and took it out on Murray . . . You don't throw people like Eddie out of games. He enticed Eddie into the ejection. He cause the whole thing. An umpire can't make a much worse mistake."

Oh, that's not the half of it.

Both teams played the game under protest after a seventh-inning rhubarb over a foul tip in which Oakland Manager Billy Martin, storming and stomping (although not with Weaver's elan), pulled his whole team off the field. What Martin was really protesting was his team's fifth straight loss, sixth on this seven-game road trip and 12th defeat in 20 games since their 17-1 binge to start the year.

However, this game had drama as well as shenanigans.

The Birds took a 2-0 lead in this drizzle-soaked affair on a two-out, two-run infield hit by Mark Belanger in the second inning on which daring or dumb (pick one) Rich Dempsey scored from second base on a bouncer off the third baseman's chest that never went more than 120 feet from home plate.

The O's then broke the game open in the seventh, after perhaps stiffening up the arm of A's starter Matt Keough with their stalling and complaining. Ken Singleton hit a two-out, two-run double up the gap in left center field for a 4-1 Baltimore lead. On a night with such an excess of riches, that naturally moved Singleton ahead of the A's Tony Armas in the AL RBI lead (26).

Amid all this high-powered entertainment, Oakland's true star -- Rickey Henderson, the man with 100 steals and 300 times on base in 1980 -- played a game that was, for him, both exemplary and typical.

Offensively, Henderson was the only man to reach base against McGregor with a soft single to right in the fourth on a changeup, a double off the 376-foot sign in left on a 3-1 ineffective fast ball in the seventh and a spanked double into the right field corner on a fast ball with two outs in the ninth.

Defensively, Henderson was better. He robbed three Orioles of almost certain doubles with all-out running catches, twice going into the corner, once into the alley. His flat out, tip-of-the-webbing theft off Dempsey's hooking liner in the eighth was one of those rare plays that seemed impossible, even to the most sated taste. Henderson also held one line hit into the corner to a mere single with a fine throw to second. Later, when DeCinces, after driving home the fifth Oriole run in the eighth with an RBI liner off the wall, decided, What the heck, make the guy throw me out, Henderson obliged by making a throw to second that nailed the stunned DeCinces by 30 feet.

If ever two teams were moving in opposite directions in a big hurry, it's these two. The O's, who have won 15 of 18, are finding out how good they really -- "better and better every year. We just keep improving," said McGregor. The A's, by contrast, are learning their limits. For instance, Belanger's two-run hit would have been a third out if Dave McKay weren't a candidate for worst hot corner man in the league.

Also, any team with a solid bullpen would have yanked Keough before he ever gave up the game-clinching double to Singleton in the seventh, let alone DeCinces' RBI rip in the eighth. However, Keough was left in for a meaningless complete game that gave him his first defeat (6-1). Finally, the bottom half of the A's lineup against left-handed pitching is a disaster. The final five batters -- Mike Heath, Jeff Newman, Shooty Babbit, McKay and Rob Picciolo -- went zero for 15 tonight and looked in character doing it.

In fact, the O's, who have made their recent rush with little fanfare, have an interesting opportunity when they close their miniseries with the A's here on Tuesday; if the Orioles win, it will be they, not the A's who have been on magazine covers and television specials for the last month, who will have the best record in the AL.

Above all, however, this was McGregor's night.

"Scotty was dealin' tonight," said Dempsey. He wasn't talking about just McGregor's textbook statistics: 110 pitches, 78 strikes, 54 fast balls, 40 changeups (32 for strikes) and 16 curve balls. From the stands, McGregor looked, as always, like a man flirting with disaster on every modest pitch.

But from behind the plate, McGregor, now 4-1 with four consecutive wins, a 2.13 ERA and back-to-back three-hitters, looked like what he is: unhittable when sharp. And since mid-1979, McGregor has been getting even sharper ever more often, building a 37-15 record (.712) and a soaring reputation.

"His ball is always rising, sinking or sailing. It comes up there saying, 'Hit me,' then it darts and it's like there's no ball there at all," said Dempsey.

When that happens, as the A's discovered tonight, it's tough to beat a mild mannered lefty with both charisma and an invisible pitch.