With the outline of a baseball diamond painted on the playing field, approximately 500 D.C. United fans gathered at RFK Stadium last night to celebrate the team's victory in Sunday's MLS Cup.

Besides applauding the efforts of the players and coaches, fans capitalized on the gathering, which included District Mayor Anthony A. Williams, by expressing their views on issues such as sharing the stadium's field with a baseball team and the possible construction of a soccer-only stadium.

Shouts of "No infield at RFK!" and "Keep the grass alive!" emanated from the crowd as players and city officials took the stage for a short ceremony. One of the loudest cheers occurred when Williams reiterated his pledge to have a soccer stadium built near the Anacostia waterfront by 2007.

"This is a growing sport in our area, and it's a real morale boost and economic engine," Williams said. "That's why we proudly support it, and that's why we're very excited about building a new stadium."

The baseball diamond outline served as a visible reminder for fans who voiced varied opinions about the prospects of sharing RFK with a major league baseball team next year.

United fan Kyle Morrisey of Alexandria said that he would not mind a baseball team playing at RFK "as long we have a grass field and I have a [soccer] stadium in 2007."

Shawn Cole, a United season ticket holder and baseball fan from Reisterstown, Md., said that he was against a baseball team playing at RFK partly because he feared the size of the section of seats in which he normally sits might be decreased.

"We would probably end up losing a row or two to the dugout, which doesn't necessarily make me happy," Cole said.

Fans roamed the playing field all evening and kids played games using goals that were set up at both ends of the field.

Players proceeded through the crowd to the stage with team captain Ryan Nelsen hoisting the MLS Cup -- United's fourth league championship trophy. Afterward, the players were available for autographs. Freddy Adu was mobbed by fans and was led off the field by security after saying the show of support was "awesome."

"To hear the cheers and the chants . . . it makes [training] all worthwhile," Nelsen told the crowd.

The level of access to the team and the field impressed many fans, including Suzanne Butler of Bowie.

"You don't get this in all the sports," she said. "They're not making millions of dollars. They sign autographs for the fans and they're active in the community. That's what we like about soccer."

Louise Moreno, wife of United star Jaime Moreno, holds their daughter Sabianna, 4, at rally.