We got beat by a bunch of hockey players from Canada!
Not really. Dontrelle Willis certainly did. He had two horrible starts, undermining the good ones by Clemens and Peavy. But the manager, Buck Martinez, was a large part of the problem. He had no strategy for scoring runs when the homeruns weren't coming. With players like Damon, Utley, Young, etc., I woudl have used the hit-and-run a good bit, stolen some bases, bunted. Instead, we waited around for the homers to come. We only beat Mexico the first time with two solo HRs from Chipper Jones and Derrek Lee.
American players are unmotivated and spoiled by money. In basketball, USA lost to Italy and Argentina in 2004.