ST. PETERSBURG, FLA., NOV. 29 -- For a while, it looked like the United Nations might have to step in to resolve the disputes that have cropped up between Australia and the United States prior to this weekend's Davis Cup competition.

Instead, beginning Friday night, the two teams will settle their scores on the tennis court, as the 1990 final round gets underway at the Florida Suncoast Dome.

In a surprise move before today's draw, Australian team captain Neale Fraser announced that Pat Cash, Australia's most-talented player and a one-time Wimbledon titlist, will play doubles rather than singles during the three-day tournament.

As a result, the first singles match will feature American Andre Agassi, the fourth-ranked player in the world, against Australian 20-year-old Richard Fromberg, ranked No. 32. In the second match, 15th-ranked Michael Chang will play Australian Darren Cahill, ranked 57. "We looked at the overall picture of the team and their chances of winning," Fraser said. "We picked players who we think will win."

On Saturday, Cash and John Fitzgerald will play the heavily favored team of Rick Leach and Jim Pugh. The singles players swap opponents for the final two matches on Sunday. Each match is best of five sets.

Fraser's decision was an obvious concession to the American team's choice of playing surfaces -- slow, red clay that baseline artists Chang and Agassi love and that the big-serving Cash loathes.

Cash never has played as well on clay as on grass, the fastest surface and one used widely in Australia. Furthermore, after winning Wimbledon in 1987, he severely injured his Achilles' tendon and was sidelined for nearly a year. His ranking plummeted to No. 80.

"The two {singles} players we selected have been our most consistent players on clay for the last two years," Fraser said. "They are young and they are enthusiastic."

The verbal fracas over the surface began immediately after the United States defeated Austria, 3-2, in the semifinals in September. U.S. officials announced plans to import red clay from Germany for the matches, but the Australians cried foul, saying that the surface is not "in general use" in the United States. In response, the United States extended the olive branch -- sort of -- by agreeing to use home-made red brick dust that is slightly grainier than the powdery European clay.

Today, U.S. players were hardly apologetic as they explained their strategy in seeking their first Davis Cup title since 1982.

"Clay is obviously our best surface and, more important, it's probably Australia's weakest surface," Agassi said. "Why not pick a surface that is great for us and not for them? Isn't that what it's all about?"

Agassi and Chang, who have practiced in the cavernous 22,000-seat dome this week, said the American clay is comparable to the famous slow stuff at Stade Roland Garros in Paris. That's where Chang won the French Open in 1989, and where Agassi was runner-up this year.

The clay is not the only thing aggravating the Australians, who last won the Davis Cup in 1986. Fraser also has said the schedule of matches -- singles begin at 5 p.m. Friday and doubles start at 12:30 p.m. Saturday -- was a disadvantage to his team because he originally thought about using Cash for both singles and doubles, but that would have left him very tired.

"We've tried, we've argued, we've petitioned," he said. "Everyone agrees it's wrong, but somehow we can't get anyone to make the decision" to change it.

Although the prestigious 90-year-old tournament was designed to promote goodwill among nations, this year's competition is showing strains even within teams. Several top U.S. players, including Agassi and John McEnroe, were reluctant to volunteer their services. Three other singles players -- Brad Gilbert, Aaron Krickstein and Jay Berger -- played the early rounds.

U.S. team captain Tom Gorman and David Markin, president of the U.S. Tennis Association, reportedly agreed to guarantee a spot for Agassi in the final if he played in the semifinals against Austria. In addition, the rebellious Agassi, who has proclaimed that he doesn't altogether fit in with his straight-laced teammates, was allowed to take his personal entourage to Vienna.

For his part, the serious and deeply religious Chang seems to be the prototypical patriot the American team has been looking for. Down two sets to none in the final match against Austria, the 18-year-old fought off cramps and defeated Horst Skoff in five sets to advance the United States to the final round.

Unlike the Australians, who view the competition as a proud tradition, Chang admits that he hardly paid attention to the Davis Cup when he was growing up. But he said today that "the longer you're on the tour the more you realize how special it is. It's definitely an honor."

"We aren't playing for ourselves," he said. "We're playing for our team and our country."