The Americans battled to a 25-17, 25-22, 25-21 victory to begin group play and demonstrated they are ready to challenge for another Olympic title.
The United States' men's team defeated Brazil in the gold medal match four years ago to win their first Olympic championship in 20 years.
Next up for the Americans will be Germany on Tuesday, after which Team USA will face Brazil, Russia and Tunisia.
The top four teams from each of the two six-team groups will advance to next week's quarterfinals.
Russia defeated Germany in three sets in another Group B match Sunday while in Group A Bulgaria blanked Britain, Argentina won in three sets over Australia and Poland needed four sets to dispose of Italy.
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