Today at RFK Stadium, while D.C. United's depleted defense is keeping a close eye on Tampa Bay Mutiny striker Raul Diaz Arce, club and stadium officials will be watching Diaz Arce's loyal fans.

Diaz Arce, United's most popular player during his two seasons here, is making his first appearance in Washington since United's home opener against the Salvadoran's former team, the San Jose Clash. That night in April, United drew 35,167--the largest regular season crowd in its four-season history--but many were there to show their support for Diaz Arce and Salvadoran teammate Ronald Cerritos and razz United's baffled players and fans.

Many in the Latin American community have not forgiven United for trading Diaz Arce to New England after the 1997 season. The club said it had no choice because of a salary cap predicament, but his backers say another star should have been dealt instead.

The game in April turned unruly and an apparent lack of control by stadium security worsened the situation. Witnesses reported numerous fights in the stands and parking lots, beer being thrown on unsuspecting spectators and fans sitting in seats reserved for others and then refusing to move. Many upset fans said they would never return.

Since then, the club has worked with stadium officials to improve security, and there haven't been nearly as many problems. But with Diaz Arce back in town and a crowd of about 20,000 expected, United isn't taking any chances.

"We'll have a slightly different security set-up than we've had in the past," United President and General Manager Kevin Payne said. "We're going to have more police on the concourses after the game and in the parking lots, more security in the stadium during the game. We think it will help.

"It's our hope that the Salvadorans will come and be respectful of the people around them. They certainly have every right to cheer for whomever they wish. As long as they behave appropriately, we're fine with it."

Today is not the day for United to have problems, not with the game being shown live on national network television and with new Major League Soccer commissioner Don Garber and D.C. Mayor Anthony Williams scheduled to watch from Payne's private box.

Diaz Arce, playing for his fourth team, is MLS's second all-time leading goal scorer behind United's Roy Lassiter. In El Salvador, where he has starred for the national team for several years, he is a national hero. His following carried over in Washington, where there are thousands of Salvadoran immigrants.

"D.C. should have realized what the reactions were going to be when I was taken off the team," Diaz Arce said in a league-sponsored on-line chat Thursday. "The team never took into consideration the fans' loyalty, not only to me but to the whole team."

Nonetheless, United's attendance hasn't suffered. Although many Salvadoran Americans have been staying away, D.C. leads the league with an average of 18,712 fans per game, an increase of about 17 percent over last year.

Today the crowd will see a United team that is trying to recover from a 4-3 loss to the minor league Charleston Battery on Wednesday night in a U.S. Open Cup tournament match.

Said Coach Thomas Rongen: "It was a very negative experience in that we learned a very, very hard lesson at a time we didn't want to learn it: losing to an opponent we weren't supposed to lose against. That hurts. Everyone will be better for it, which means I think the guys will come out [today] with a lot of aggression and redemption on their minds."

United will have to do it without all-star defender Carlos Llamosa (quadriceps injury) and probably without all-star defender Diego Sonora (strained groin muscle).

Data: vs. Tampa Bay Mutiny

Where: RFK Stadium

When: 2 p.m.

TV: WJLA-7, WMAR-2

Radio: WACA-1540 (Spanish)

Tickets: $13-$34

Records: United 13-7, 33 points; Mutiny 9-12, 19 points

D.C. Probable Starters: GK -- Tom Presthus; D -- Jeff Agoos, Eddie Pope, Carey Talley; MF -- Richie Williams, Geoff Aunger, John Maessner, Chris Albright, Marco Etcheverry; F -- Jaime Moreno, Roy Lassiter (15 goals, 7 assists).

Mutiny Top Players: MF Carlos Valderrama, F Raul Diaz Arce (9 goals, 6 assists), MF Steve Ralston, F Musa Shannon, GK Scott Garlick