BUENOS AIRES, Argentina -- An injury-time blast gave the United States a 1-0 win against Ecuador in its opening match of the Under-20 World Cup on Saturday.

After little inspiration from both teams in San Juan, left back Jonathan Gomez shot from the edge of the box one minute before the final whistle to beat goalkeeper Gilmar Napa.

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Until Gomez's winner, the best opportunity was on the hour after an embarrassing mistake by Ecuador's Napa. His clearance hit his defender Christian Garcia in the face. The ball fell to American striker Diego Luna, who shot wide despite the empty goal.

Ecuador, the team of teenage sensation striker Kendry Paez, did not produce a single shot on target.

The U.S. ended the first round of games in second place in Group B after Slovakia beat Fiji 4-0. The Americans could now secure its spot in the next round with a win against Fiji on Tuesday. The same could happen to Slovakia in its match against Ecuador.

The first goal of the tournament came from New Zealand, for which Norman Garbett scored the only goal in the 80th minute to beat Guatemala in a Group A game.

Later, Argentina beat Uzbekistan 2-1, with all three goals coming in the first half.

Argentina inherited Indonesia's spot in the tournament as host. Protests in Muslim-majority Indonesia against hosting Israel forced FIFA into a very late switch of venues. Indonesia does not have formal diplomatic relations with Israel.