RIO DE JANEIRO (AP) — Argentina's handball team rescued tennis player Juan Martin del Potro from an elevator, but couldn't rescue themselves from an opening-match loss to Denmark on Sunday.

Argentine player Federico Pizarro heard shouting coming from an elevator in the athletes village and opened the door to find del Potro, who had been trapped there during a power outage.

Gonzalo Carou said the team found the incident "funny," but said it could have been less amusing if del Potro's preparations for his match against top-ranked Novak Djokovic had been disrupted.

They weren't. The 2009 U.S. Open champion beat Djokovic in straight sets in the first round of the Olympic tennis tournament.

A few hours later, however, Argentina lost its handball opener against Denmark, falling 25-19 in Group A. The Danes received passionate support from the Brazilians in the crowd because of the host nation's traditional rivalry with neighbor Argentina.

Qatar won on its debut in the men's Olympic handball tournament, and then courted controversy with its mostly international team.

Foreign-born players led the way in a 30-23 win over Croatia, although it wasn't always easy for Marko Bagaric, who is originally from Croatia but played for Qatar.

"The worst feeling was during the national anthem. Ah, but what can I do?" Bagaric said. "Qatar gave me the opportunity to play in the Olympic Games. It is the dream of any sportsman."

The gas-rich Middle Eastern country has made a rapid rise in the world of handball with a team largely recruited from veteran foreign players with little previous connection to Qatar, coming second at last year's world championship.

That has led to accusations from rivals that the Qataris are simply trying to buy their way to medals by fielding a group of international players rather than a true national team.

Qatar's top scorer was Montenegro-born Zarko Markovic with 10 goals, followed by Cuba-born Rafael Capote with six. Players originally from France, Bosnia and Egypt also scored.

Qatar's cosmopolitan lineup is possible because of International Handball Federation rules allowing players to switch allegiance if it has been more than three years since they played for another national team. The win over Croatia strengthened Qatar's hopes of qualifying for the quarterfinals as one of the top four teams in Group A, while Croatia also remains in contention.

It was also a day for the goalkeepers to shine — and not just with saves.

France keeper Vincent Gerard lit up his team's 25-23 win over Tunisia with a full-court shot into the goal. France is aiming to become the first men's team to win three consecutive Olympic gold medals.

Earlier, Brazil goalkeeper Cesar Augusto Almeida had scored in similar fashion as his team delighted the home crowd by edging Poland 34-32 in the highest-scoring game yet at the Rio de Janeiro Olympics. It was only the Brazilian men's fourth Olympic win in 24 attempts.

Also Sunday, European champion Germany started with a 32-29 win over Sweden in Group B. Julius Kuhn led Germany with seven goals, while Jerry Tollbring had eight for the Swedes.