John Lowenstein seldom is at a loss for a theory, frequently offering one coming from the direction of his position with the Baltimore Orioles--left field. Tonight, however, upon completing an astounding season against the Kansas City Royals in a 12-4 victory spree, Lowenstein foundered in the explanation department--his only failure of the night.

"It's not something easily explained, or anything to ponder for any length of time," he said, referring to his .625 batting average (15 for 24) against the Royals this season. (He hit .429 against them last year.)

Tonight, Lowenstein headlined the Orioles's offense with a run-scoring single, double, walk, triple and--while admittedly trying for a home run and the cycle--another double. He scored three times.

"I'm not that impressed with statistical accumulations, other than it being extraordinary over a long term," Lowenstein said. "It certainly leans more toward coincidental than anything else. I've done exceptionally well against certain teams one year, then been dramatically impotent against the same ones the next year."

In the ninth inning, Orioles breezing toward their seventh straight victory with an 8-4 lead, Lowenstein geared up for a home run swing. "I wanted the first pitch, a slider down the heart of the plate," he said. "But it probably would have gone to straightaway center, anyway." Instead, he pulled a bouncing double into the corner in right field.

The man following him in the lineup, Ken Singleton drove in four runs and scored two with a run-scoring ground out, two-run home run, run-scoring single and a walk. His 16th homer and a homer by Cal Ripken soared deep to center field, giving the Orioles four over the 410-foot mark in two nights.

For the second night, Ripken got the official game-winning run batted in in the first inning, on a weakling of a single this time. His homer, No. 21, was his second to dead center in a two-game sweep at Royals Stadium. He leads the team with 82 RBI and 15 game-winners.

Rich Dauer contributed a sacrifice fly and two-run single, Rick Dempsey a sacrifice fly and Todd Cruz a run-scoring double.

Storm Davis (11-5) benefited from the potent offense. He won for the first time in four starts since Aug. 3, worming out of trouble spots with plenty of lead to work on.

Today, for the 83rd day this season, the Orioles woke up leading the East Division, keeping all challengers at arm's length. Milwaukee beat Seattle, 3-2, remaining 2 1/2 games behind, and Detroit, in beating Minnesota, 4-3, stayed three games back. The Royals lost the second of three series on a long home stand (5-5), and they limp into Chicago to challenge the White Sox twice from far back in second place.

Tonight, Royals starter Eric Rasmussen (2-3) lasted just one out longer (six outs) than Gaylord Perry did Monday against the suddenly alive Orioles bats, which have averaged more than 13 hits a game the last five days for a .366 average (67 for 183).

"I knew we'd start hitting soon," Singleton said. The Orioles had been in a three-week slump, averaging in the low .220s. "We're just too good not to. And we wouldn't win this thing if we didn't start now."

Lowenstein commented, "We know the talent is there, the capability exists. So you try not to concern yourself with it, just deal with it psychologically until things turn around. Every team is afflicted with this general malaise offensively. It's a matter of how well you rebound when you recover, and maximize the wins in a streak."

The Orioles worked up a 3-0 lather in the first inning, produced this time by scattershot, not the sonic boom of the night before--Ripken's homer.

The first three batters--Al Bumbry, Dan Ford and Ripken--hit singles, however lightly, that produced the first run. The first two bounced over second base, barely out of reach of reserve second baseman Greg Pryor. Ripken's was a looping fly to short right field. A one-out single by Lowenstein and a routine ground out by Singleton padded the lead.