Recent improvements in the performances of the Mexican national team have attracted the interest of European clubs, who have started snapping up the country's top players.

When Mexico left for the World Cup, only four of their 23-man squad were based abroad.

The total has more than doubled in the month since they lost 2-1 to Argentina in the second round, with defenders Ricardo Osorio and Carlos Salcido, team captain Pavel Pardo and strikers Omar Bravo and Francisco Fonseca all moving abroad.

Mexico's World Cup coach Ricardo La Volpe has said Mexican players need the experience of playing in Europe if the country wants to become a major soccer power.

But it remains to be seen what effect the new phenomenon will have on the championships which has traditionally been an importer rather than exporter of players.

As usual, the 2006-07 season will be divided into two separate championships, the Apertura and Clausura.

In each tournament, the 18 teams play each other once but are divided into three groups. The top two in each group qualify for the knockout stages along with the two best of the remainder.

Relegation is decided over three seasons, or six tournaments, meaning that a team can reach the quarter-finals while still fighting against the drop.

Provincial clubs Toluca and Pachuca won the two championships played last year and the big city teams from Mexico City, Guadalajara and Monterrey, will be determined to bounce back.

Of Mexico City's quartet, America appear the best placed to make a challenge although they will be missing playmaker Cuauhtemoc Blanco because of injury for the early rounds.

Luis Fernando Tena has replaced Manuel Lapuente as coach and the Eagles have signed Paraguayan forwards Salvador Cabanas and Nelson Cuevas although they have sold captain Pardo to VfB Stuttgart.

America are away to San Luis, runners-up in the 2005/6 Clausura tournament, on Saturday.

Cruz Azul have sold Mexico striker Fonseca to Benfica while UNAM will this time be more worried about relegation after three disastrous tournaments.

Brazilian Ricardo Ferretti is their third coach since Sanchez resigned last October.

Atlante are considered the ugly ducklings in the capital, routinely attracting only a handful of fans to the giant Azteca stadium.

Monterrey have retained coach Miguel Herrera despite their poor showing last time around while neighbours UANL have signed coach Jose Luis Trejo, who led Pachuca to the title in the last tournament.

Former Mexico coach Enrique Meza has replaced Trejo at Pachuca, who start the defence of their crown at home to Cruz Azul on Sunday.

Guadalajara, the country's most popular club and the only one not to field foreigners, are likely to face Toluca with their reserves on Sunday.

Oddly, the Chivas also have a friendly against European champions Barcelona in Los Angeles on the same day.