CARLSBAD, Calif. (AP) _ The United States, defending Davis Cup champion, is talent-laden again this year. Team captain Tom Gullikson won't guarantee another title, however.

The heavily favored U.S. team, which completed a 5-0 sweep of Mexico on Sunday, will travel to the Czech Republic, which swept Hungary, for second-round matches April 5-7.

Gullikson, asked if anything less than another championship would be considered a failure by the U.S. team, said that strange things can happen in Davis Cup play, noting India's first-round upset of the Netherlands and Italy's upset of Russia, which lost to the United States in last year's final.

``What you want to do is use the best players available and put forth the best effort possible,'' Gullikson said. ``That's all you can do.''

He cautioned that the Czechs, particularly Petr Korda, can be ``explosive,'' saying that when he's on his game, Korda is hard to beat.

Todd Martin, who won his two singles matches against Mexico, agreed with Gullikson about the Czechs.

``They're dangerous,'' Martin said. ``They're explosive and unpredictable. Korda is like a bomb; You never know when it's going to go off.

``Korda has beaten the top players in the world, and you always wonder when he's going to have a great day. Hopefully it's not against us in the Davis Cup.''

Said Michael Chang: ``The next (matches) will be more difficult. Korda's a shotmaker, he can hit winners all over the court. And (Daniel) Vacek's a good player, too. Playing over there, it won't be that easy.''

Whatever the makeup of the U.S. squad for that round, Chang doesn't figure to be on it.

``I don't think I'm going to play; schedule-wise, I'm going to be in Asia,'' said Chang, whose appearance against Mexico was his first in Davis Cup since he helped the United States end an eight-year title drought in 1990.

``I'm not sure whose schedule fits it well. Jim (Courier), I think, will be in Europe.''

Chang, who started the sweep of Mexico by beating Leonardo Lavalle on Friday, downed 18-year-old Alejandro Hernandez 6-0, 6-2 on Sunday. Martin, who defeated Hernandez the first day, beat Lavalle 3-6, 7-6 (7-1), 6-4 Sunday as the Mexicans won their only set of the five matches.

The United States clinched the first-round victory on Saturday when Patrick McEnroe and Patrick Galbraith beat Lavalle and Oscar Ortiz in doubles, essentially turning Sunday's singles into exhibition matches.

Although Gullikson said earlier that he expects to use eight to 10 different players for Davis Cup during the year if the United States keeps winning, he hasn't said which players.

He indicated that Pete Sampras, who led the United States past Russia in the title matches last year, will play some this year, but that Andre Agassi is leaning toward the Olympics instead.

Gullikson also said he had spoken with Courier about playing against the Czechs, but nothing had been finalized.

The Czech Republic had no problems disposing of Hungary 5-0, as did Germany over Switzerland and France over Denmark in the World Group, the only 16 nations who actually compete for the international team trophy.

In other World Group matches, Italy shocked Russia 3-2, India surprised the Netherlands 3-2, and Sweden defeated Belgium 4-1.

Austria and South Africa split their first two singles matches in their competition in Johannesburg. South Africans Wayne Ferreira and Gary Muller led Thomas Muster and Alex Antonitsch of Austria 6-3, 7-6 (7-3), 6-7 (5-7), 1-2 when their doubles match was suspended Sunday night because of darkness.

The matches will be completed today, with the winner to face Italy in the second round.

Other second-round matches will send Germany against France and India against Sweden.

In American Zone Group 1 play, Venezuela edged Canada 3-2, Brazil defeated Chile 3-2 and the Bahamas nipped Peru 3-2. American Zone Group II winners included Ecuador, Uruguay, Cuba and Colombia.

In Asia-Oceania Zone Group I, winners were New Zealand, Australia, South Korea and Japan, while in Group II, Hong Kong and Thailand were victorious.