SCOTTSDALE, Ariz. — Johnny Damon and his U.S. teammates had a hard time figuring out exactly what needed to happen for the Americans to advance in the World Baseball Classic.

It was complicated — and it all worked out fine for the U.S. team on Thursday night when Mexico scored four runs in the top of the first inning of a 9-1 victory over Canada.

"This tiebreaker stuff, you've got to go to school for it," Damon, the New York Yankees' latest superstar addition, said in the Scottsdale Stadium dugout before a workout earlier in the day. "I thought there would be a clear-cut winner and a clear-cut loser. ... It's definitely a weird feeling."

After losing to Canada 8-6 in a first-round game Wednesday night, Team USA's fate Thursday was in the hands of the Canadians and Mexicans.

If Canada had won and the United States defeated South Africa today, the Americans would reach next week's second round in Anaheim, Calif. Even if the U.S. team were to lose to South Africa, it would have to get beat by more than seven runs because Team USA has the tiebreaker against Mexico after its 2-0 win Tuesday.

Even with Mexico's win, Team USA could move on because Mexico scored at least three runs. Mexico ended that suspense with four straight doubles off Canada starter Jeff Francis to take a 4-0 lead.

The three-way tiebreaker is based on runs allowed.

In this odd system, the United States would've been eliminated — before it played South Africa — if Mexico had beaten Canada by scores of 1-0, 2-0 or 2-1.

It made for a tense day for the U.S. squad, with most players making plans to monitor the game.

"Most guys are reflecting on the tiebreaker scenario — 'What's the scenario?' Obviously we never talked about the tiebreaker scenario before the tournament," manager Buck Martinez said. "We have to win and get some help. These are the perils of international play."

Roger Clemens is set to pitch for Team USA Today at Scottsdale Stadium, though most players on the team wished they could play again Thursday and get a chance to bounce back from the demoralizing performance against Canada.

Martinez compared the feeling to losing a playoff game in October.

"It was almost worse," reliever Joe Nathan of the Minnesota Twins said. "It's like this feeling that you just let a whole lot of people down. I know for myself, I don't want to feel that way again."