BALTIMORE -- Chris Gomez doesn't play too often, so when he came to the plate in the sixth inning with the bases loaded and the Baltimore Orioles trailing by two runs, he tried not to get caught up in the moment.
"In situations like that, you just try to relax," Gomez said. "It's real easy to get too excited in a big at-bat, so you try to tone it down as much as possible and just try to get a pitch to hit."
Gomez found a 3-1 fastball from Joel Peralta much to his liking, and he deposited it into the left-field seats. The grand slam capped a comeback that carried the Orioles past the Kansas City Royals, 6-4 Saturday night.
It was the second career grand slam for Gomez, a utility player who started the night with only eight at-bats this season.
"He's just a professional," Orioles manager Sam Perlozzo said. "He came up big for us tonight."
Alberto Castillo had two hits and scored two runs for the Orioles, who trailed 4-1 in the fifth. By taking the first three games of the four-game series, Baltimore (6-6) reached .500 for the first time since last April 28.
Miguel Tejada led off the sixth with a single and Aubrey Huff drew a walk before Peralta (0-1) replaced starter Odalis Perez. Kevin Millar followed with a popup to short center, but the ball fell in when the Royals had a difficult time determining who should make the catch.
"The center fielder, in my eyes, has a better chance on that ball than the shortstop," Royals manager Buddy Bell said. "He's going way out in no man's land. When the infielder goes out that far, an alarm clock goes off in your head ... and that's when the play gets messed up."
That loaded the bases for Gomez, whose liner that barely made it out.
"I knew I hit it well," he said. "Either way, if it went out it was great, obviously. If not, it was at least sac fly. That would have been good, too. Either way, it was looking good."
His only other grand slam came on April 22, 2004, for Toronto against Boston's Curt Schilling.
Peralta lamented the missed popup, but blamed himself for falling into a 3-1 hole to Gomez.
"That was the whole problem. I fell behind the hitter and he got me," the right-hander said. "That was the game right there."
Scott Williamson (1-0) earned his first win with Baltimore with an inning of one-hit relief. John Parrish struck out the side in the seventh, Jamie Walker worked a perfect eighth and Chris Ray got three straight outs for his third save.
Orioles starter Daniel Cabrera allowed four runs, three earned, and seven hits in five innings. The right-hander struck out five, walked one and hit two batters.
Mark Grudzielanek had two hits and scored twice for the Royals, who have lost seven of eight. Kansas City is 3-9, tied with Washington for the worst record in the majors.
"I don't really know how to describe this one tonight," Bell said. "We had chances, they had chances. Tough night."
Early on, the Royals appeared destined to win their first game in Baltimore in six tries since May 6, 2005.
Kansas City scored two first-inning runs, matching its total output for the first two games of the series. Cabrera hit leadoff hitter David DeJesus with a pitch before singles by Grudzielanek and Mark Teahen loaded the bases. After Reggie Sanders hit into a run-scoring double play, Ross Gload drove in a run with an infield hit.
A steady rain began in the third inning and continued to the end of the game, but did not appear to have a noticeable influence on play in the field.
The Royals went up 3-0 in the third. A walk and a hit batter loaded the bases with two outs before a passed ball by Castillo produced an unearned run.
"We had some momentum going in our favor," Bell said. "Odalis made some good pitches when he had to, we had some double plays, we had some key outs when we had to."
At that point, Perlozzo became worried that the rain would stop play before the Orioles could come back.
"My biggest concern was that the rain didn't get harder and we could continue playing, because I thought we had a shot," he said.
Singles by Castillo, Brian Roberts and Nick Markakis gave Baltimore its first run in the bottom half.
In the fifth, Grudzielanek led off with a double and scored on a grounder by Sanders.
The Orioles closed to 4-2 in the bottom half when Castillo doubled and scored on a single by Melvin Mora.
Teahen's first-inning single snapped an 0-for-16 skid. ... Cabrera has allowed only three walks in three starts; he led the AL with 104 walks in 2006. ... Baltimore had a season-high 13 hits.