By Brian Trusdell

Two titles, four appearances in the finals and seven of eight semifinalists. Mexico teams have dominated the CONCACAF Champions League since its inception and many aren't predicting a change in the pattern until somebody proves they're better.

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"Just one of the important factors that they've always had is their depth is so strong and they have such a great financial funding that they can take the chances in the Group Stage, and if they need it, they've got six incredible substitutes on the bench," said former U.S. Olympic captain Brian Dunseth, now an analyst for Fox Soccer Channel in the United States.

"At the end of the day, you look at the strength of their squads, from development, from reserve to first team, they have everything to play for. Especially once they get to the quarters, semis, you start to see that focus change, you start to see the pressure from the press really step up."

Cruz Azul, a loser in the final to fellow Mexican sides Atlante in 2009 and Pachuca in May, is back for a third try. Santos, after a one year absence, is back, along with last year's semifinalist Toluca and newcomer Monterrey.

The Preliminary Round begins Tuesday with four matches, including Santos at San Juan Jabloteh and Cruz Azul at San Francisco.

The two-leg Preliminary Round winners then advance to the six-round Group Stage, which commences August 17 and concludes October 21, whittling the field to the eight knockout-round survivors.

In the two years since Champions League was started, Mexican clubs have won 50 of 89 games with 18 draws.

The closest any team other than a Mexican side has come to the title match was the Puerto Rico Islanders, which lost out on penalties to Cruz Azul in the semifinals in 2009. Other than, no club has gotten past the semifinals.

The Islanders, who have claimed more than their share of upsets in the first two years of the Champions League, have another daunting Preliminary Round challenge. After upsetting Alajuelense of Costa Rica the first year, and Major League Soccer side Toronto FC last season, the reigning Caribbean club champ must get past the Landon Donovan-led Los Angeles Galaxy this time.

It faces off the Galaxy in the first leg of their Preliminary Round series on Tuesday in Los Angeles.

"They have wonderful players all around the park," Islanders goalkeeper Bill Gaudette said. "It's going to be a difficult game for us. We have two chances to give them a game, and we're going to see what happens. We'll go out to LA and give it our best and they have to come down to Puerto Rico, which not many teams like to do."

Marathon of Honduras has made it to the quarterfinals both years before being eliminated, first by the Islanders in 2009 and then Pumas this past season. But it will have to compensate for the loss of last year's club scoring leader Walter Martinez, who has returned to Beijing Guoan in China.

Unlike their Mexican counterparts, American teams from MLS have struggled. Of the eight teams that have played, only two have reached the quarterfinals: Houston in 2009, and Columbus this past season.

Two years ago, neither MLS team that played in the Preliminary Round were able to get to the Group Stage, and last year, the New York Red Bulls were unceremoniously eliminated by Trinidad's W Connection.

Dunseth, who played with seven different teams in MLS and in the CONCACAF Champions Cup, believes at some point the U.S. teams' resolve will stiffen.

"How many times do you get tired of having your head handed to you?" he asked rhetorically. "How many times do you get tired of playing against a team, knowing it's not their first team, and losing? How many times do you get tired of watching (USSF D2) them do pretty well, or compete at a similar level, or end up with the same number of points you have in the group stage, at what point does it start really angering you? At what point does it become a pride issue?"

This may be MLS' best chance to make a dent in the Champions League with the Los Angeles Galaxy, Columbus Crew and Real Salt Lake holding the three best records entering the continental championship. Only Seattle has a losing record, and even Toronto, who qualified as Canada's champion, has lost only one of its previous 13 matches heading into its game Saturday against Dallas.

MLS, the USSF D2 league and Trinidad & Tobago are already in the middle of their seasons, while Costa Rica, Guatemala and Mexico begin their Apertura championships this weekend, and El Salvador, Panama and Honduras not for at least another week.

It may give the teams in middle-of-season form and advantage, but the length and nature of the competition still will come down to a simple formula.

"For teams outside of Mexico," Dunseth says, "if you can win your home games, and you can pick up a couple of draws on the road you're going to qualify for the quarterfinals."