PREVIEW-Soccer-Mexico, U.S. start qualifiers against minnows

By Brian Homewood

RIO DE JANEIRO, June 12 (Reuters) - Mexico and United States kick off their tortuous World Cup qualifying campaigns on Sunday knowing that the slightest slip-up could eliminate them after just two games.

Mexico face their tiny neighbours Belize and the U.S. host Barbados in the CONCACAF region's second preliminary round, first leg ties.

Costa Rica and Trinidad & Tobago, the region's other representatives in Germany two years ago, also enter the fray at the weekend which features a potentially volatile meeting of South American neighbours Suriname and Guyana in Paramaribo.

The eventual winners of the 12 ties will go into three groups of four with the top two in each group then qualifying for a further group of six which will determine the region's representatives in South Africa.

The system is generally disliked by the larger nations as it exposes them to the possibility of a major upset ending their World Cup hopes before the group stage even starts.

"It doesn't seem fair that we have to play a home-and-away series just to qualify for the region's group stages," United States forward Landon Donovan told FIFA's Web site (wwww.fifa.com) in April, looking ahead to the tie.

"When you meet one of the so-called smaller teams, nothing is going to be given to you. You still have to go out there and beat them," added Donovan, who won his 100th cap in the 0-0 friendly draw against Argentina on Sunday.

"Who knows, we could hit the crossbar eight times and they could have the game of their lives. We could find ourselves out of contention before the real competition even begins."