BALTIMORE, AUG. 2 -- Gregg Olson is the Baltimore Orioles' certified stopper, but Dave Johnson continues to prove deserving of a similar moniker.

When pitching after an Orioles loss, as he was tonight against the Kansas City Royals, Johnson is unbeaten. The Royals became Johnson's latest such victim as the right-hander pitched 5 2/3 innings of three-hit ball in the Orioles' 5-1 victory over Kansas City before 22,791 at Memorial Stadium.

Were it not for pain in his back and cramped legs, Johnson (11-6 and 8-0 after a loss) might well have gone longer. However, the tightening started in the second inning and got progressively worse.

Although the reason for Johnson's removal was announced as a lower back strain, he said it was his legs that caused most of the ache.

"I was in the the training room for 10 minutes," Johnson said. {The cramps were} the nastiest thing I've ever had in my life. I was in constant pain for 10 minutes."

Johnson, who said he felt "a little stiff and sore" after the game, was removed with two outs in the sixth, but by then the Orioles (52-53) had a four-run lead and were cruising to a victory in the first game of the four-game series. Every win is a critical one for third-place Baltimore, which began the night trailing division-leading Toronto by five games.

Just to make sure the Orioles didn't squander their lead, as they had the previous night, Manager Frank Robinson called on Olson with two runners on in the ninth. As usual, Olson didn't disappoint, striking out pinch hitter Mike McFarlane and Kurt Stillwell for his 25th save in 27 chances.

Duplicating their start in Wednesday night's 7-4 loss to the Blue Jays, the Orioles scored four runs in the first, all unearned, off starter Pete Filson (0-2).

"I wish we would have had six or seven," Robinson said. "{But} it was enough."

Filson should have been out of the inning by the time Cal Ripken came to the plate in the first. Dave Gallagher and Ron Kittle, teammates with the Chicago White Sox who joined Baltimore this week in separate transactions, reached safely on errors by right fielder Danny Tartabull and third baseman Kevin Seitzer, sandwiched around a walk to Randy Milligan that loaded the bases with one out.

Ripken then delivered his second bases-loaded hit in two nights -- he was only two for 19 in similar situations before Wednesday -- a triple to the gap in right-center that gave Johnson a 3-0 lead.

"It's been a gradual thing," said Ripken, still trying to recover from a protracted slump at the start of the season. "I look at it {like} I dug myself into a big hole and I'm still digging myself out."

Ripken, three for four with a sacrifice fly and eight RBI in his last five trips to the plate with the bases loaded, scored to make it 4-0 on a sharp single by third baseman Craig Worthington. But Worthington suffered a slight pull in his right hamstring on the play and was replaced by Tim Hulett.

Concerning the injuries to Johnson and Worthington, Robinson said: "We won't know more until probably in the morning. We'll check them out overnight and check them tomorrow {Friday} when they come in."

The four-run outburst gave Johnson plenty to work with. He retired the first 11 batters he faced until a two-out double off the wall in right by the American League's player of the month for July, George Brett, in the fourth.

Brett, playing for the first time since a collision Monday with Cleveland's Mitch Webster, scored on Taratabull's single to cut the Orioles' lead to 4-1. Johnson was effective for the remainder of his stint before finally succumbing to the cramps.

"I was hoping that I could go six or seven, and that they would take me out without me having to tell them," said Johnson, the staff's winningest pitcher and tied for seventh in the American League in victories. "But I didn't get that far. Twenty-four hours from now, hopefully it will be a situation that I was just losing fluids."

Catcher Bob Melvin added to the lead in the fourth with his first homer at Memorial Stadium and third of the season, a solo blast to left that made it 5-1.

Filson was removed after five, but Baltimore was just inches away from building its advantage against reliever Mel Stottlemyre. The Orioles likely would have scored at least one run in the sixth after Worthington reached safely on Seitzer's second error, but Stottlemyre was saved by center fielder Willie Wilson and first baseman Gerald Perry, each snaring a hard-hit liner.

Orioles Notes: To make room for Gallagher, who was acquired on waivers Wednesday night, Baltimore designated reliever Brian Holton for assignment before the game.

If Holton (2-3, 4.50 ERA) is not claimed by another team within 10 days, he can either go to Class AAA Rochester or reject the assignment and become a free agent; the latter would force Holton to forfeit his $347,500 salary.

"You always hope someone is claimed so he can stay in the major leagues," Robinson said. "If he's not, we'd really like him to accept the assignment and go to Rochester." . . .

Gallagher picked up his first hit as an Oriole in the seventh with a single to right. He was one for four, becoming the 39th player to wear a Baltimore uniform this season.