MEXICO CITY - Twice Olympic champions United States travel to Mexico this week for the CONCACAF region women's qualifiers wary of potential pitfalls in a small but hazardous tournament.

Only two of the six teams will qualify for Beijing and with Canada and Mexico also involved in the tournament in Ciudad Juarez, at least one of the big names will fail to qualify.

Led by new coach and former Sweden international Pia Sundhage, the current Olympic champions will be without their captain Kristine Lilly, who is pregnant with her first child.

The U.S. are in the same group as Jamaica and Mexico and start their campaign with a tough game against the hosts on Friday. Canada have been drawn with Trinidad & Tobago and Costa Rica.

"I think we're prepared, but we're definitely not overconfident," U.S. defender Christie Rampone told the U.S. federation's Web site (http://www.ussoccer.com).

The top two in each group progress and the two semi-final winners then qualify for Beijing.

The tournament starts Wednesday with Canada facing Trinidad & Tobago and Mexico against Jamaica.

"The advantage is that we're in our country," Mexico coach Leonardo Cuellar told the Mexican federation's Web site (http://www.femexfut.org.mx). "My team works with humility and we have the obligation to give Mexico a ticket for Beijing."