Castilla has yet to make an out at RFK Stadium, going 3-for-3 and driving in four runs for the second straight game to help the Nationals beat the Arizona Diamondbacks 9-3 on Saturday night.
"How about that? He's giving us all something to cheer about," Nationals manager Frank Robinson said. "Maybe he knows something about this ballpark."
John Patterson (1-1) struck out six -- all looking -- over seven shutout innings and Washington broke open a tight game by sending 11 men to the plate and scoring seven runs in the seventh.
The victory was the Nationals' fourth in a row and kept them atop the NL East at 7-4. Last season, as the Montreal Expos, the club's first four-game winning streak didn't come until May 14-18 -- and it began with the team 10-25.
But ask anyone associated with the Nationals, and they'll tell you this is not just the 67-95 Expos of 2004 by another name.
"This is a different team. We're competing really well," said Patterson, lifted for a pinch-hitter in the seventh. "Everybody's happy in this clubhouse."
That includes Castilla, the third baseman who led the NL with 131 RBI for the Rockies last season and then joined Washington as a free agent. So far, he's dispelling any notion that his stats should be dismissed as a product of hitter-friendly Coors Field.
"When I was younger, it bothered me," said the 37-year-old Castilla, who also played for Colorado from 1993-99. "People can say whatever they want."
He has reached base in all eight plate appearances at RFK, where the Nationals made their debut Thursday in the capital's first regular-season major-league game since 1971.
"I'm seeing the ball great right now and getting good swings," said Castilla, hitting .452. "The (hitting) background is great."
As part of an $18 million renovation of the 44-year-old stadium, the team put up posters on the green wall behind the fences in left field. One says "Washington," one says "Nationals" and shows Brian Schneider in his catching gear and a third features pitcher Tony Armas Jr. with the White House as a backdrop.
There was a fourth poster, emblazoned with Castilla taking a swing, when the Nationals played an exhibition against the Mets on April 3 -- but that was taken down and replaced by an ad for an auto maker.
Not to worry. At this rate, they'll build a monument for Castilla. In his RFK career, he has two homers, a triple, two doubles and a single in six at-bats. That's a 2.667 slugging percentage.
In his other two plate appearances at home, he was hit by a pitch in the eighth Thursday and walked in the second Saturday. His next at-bat, in the fourth, produced a first-pitch, two-run homer off Russ Ortiz (1-1) for the game's first runs.
"He's doing a good job of staying on the ball and not pulling off and not trying to do too much," said Ortiz, who allowed four runs in six-plus innings. "It was a good outing, but I'm never, ever happy or satisfied when we lose."
Castilla later received two standing ovations in one inning -- the big seventh. The crowd of 34,943 greeted him that way when he led off and hit a single. When the order came around again, the fans rose to salute, and he delivered a two-run double.
"It's not a Hall of Fame lineup. It's not Murderers' Row," Robinson said. "But we have the guys who can get you the big hit."
Arizona got on the scoreboard in the eighth with Luis Gonzalez's three-run homer off Luis Ayala. Even with a big late lead, Robinson needed four relievers, including closer Chad Cordero for the last out with the bases loaded.
"You're a little irritated," Robinson said, "because you have two innings two go, and you're up 9-0, and you have to go through your pitchers and use your closer."
By then, though, even with the stands much emptier than the team's debut two nights earlier -- no presidential first pitch or fireworks, either -- the fans were in another celebratory mood, bouncing up and down to make the stands sway.
"The fans seem to be real supportive these first couple of games, so that's going to help" the Nationals, Ortiz said. "You come in here and you know it's going to get loud in certain situations."
The Diamondbacks put outfielder Jose Cruz Jr. on the DL with a lower back strain and recalled Scott Hairston from Triple-A Tucson. ... Nationals shortstop Cristian Guzman went 0-for-2, dropping his season average to .122 (5-for-41).