SOCCER : U.S. FACES FIRST TEST TONIGHT.

Byline: Kevin Modesti Daily News Staff Writer

Before the World Cup, there are qualifying matches. Before the qualifying matches, there are a couple of chances for United States soccer coach Steve Sampson to test his expanding list of roster candidates.

The first of those chances comes this week, when the United States faces Peru (7 tonight at Jack Murphy Stadium in San Diego), Mexico (3:30 p.m. Sunday at the Rose Bowl) and Denmark (6:30 p.m. Wednesday at the Rose Bowl) in the fifth U.S. Cup tournament.

``We're using U.S. Cup '97 and also (an upcoming) trip to China to take a look at different players, give them some experience,'' Sampson said a few days ago. ``You cannot play well and win a qualifying phase and play well in France (site of the '98 World Cup) without 25 solid players in your pool . . . because of the possibility of injuries and yellow cards.''

John Harkes, Eddie Pope, Tab Ramos and Mike Sorber will miss the U.S. Cup because of injuries. Ernie Stewart, Thomas Dooley and goalkeeper Kasey Keller will stay in Europe with their clubs.

Eric Wynalda of Westlake, whom Sampson called ``doubtful'' for tonight's game, may play Sunday and is likely to see action Wednesday. He has been recovering from hernia surgery.

Sampson plans to take a long look at less-known players who impressed him in training, in recent international matches and, significantly, in Major League Soccer and Olympic competition.

``Prior to the MLS season, there were about 20 players with international experience who I would feel comfortable putting out there in a qualifying match. Now it's up to 30 or 35,'' Sampson said. ``I was able to watch them and monitor their progress.''

The Olympics gave younger players valuable international experience.

``That's given me confidence to call in a lot more players.''

Each U.S. game will be part of a doubleheader as the four teams play a round robin. Denmark-Mexico is tonight at 9:15, Peru-Denmark is 1 p.m. Sunday and Mexico-Peru is 8:45 p.m. Wednesday. Every game is scheduled to be shown on ESPN or ESPN2.

Because renovations are in progress at Jack Murphy Stadium, seating there will be limited to 35,000, so U.S. Soccer urged fans to buy tickets in advance.

A crowd of 60,000 was forecast for Sunday's marquee matchup between increasingly serious rivals Mexico, which won the U.S. Cup in 1996, and the United States, which won it in '92 and '95.

Mexico is coached by Bora Milutinovic, the U.S. coach for the '94 World Cup.

``Given the relationship Bora has had with the press in Mexico, he may feel more pressure to win a game with the U.S. than I do (to beat Mexico),'' Sampson said.