The United States men's water polo team opened their Olympic campaign with a tight victory over Japan in a tense, back-and-forth affair.

This was not that.

The same U.S. squad downed South Africa – the continent's lone representative in the competition – in a 20-3 demolition to go 2-0 in pool play.


Ben Hallock led the way offensively with four goals, joining eight other Americans on the scoresheet. 

Goalkeeper Alex Wolff held South Africa to three goals on 27 shots, and 11 percent conversion rate.

The U.S. faces a much more difficult test in its next match Thursday, facing three-time Olympic champions Italy, which tied Greece 6-6. After two games in Group A, the U.S. is in sole possession of first with two wins, followed by Greece and Italy at 1-0-1 and Hungary at 1-1. Japan, like South Africa, has lost both its games.

Spain leads Group B with two wins, followed by a four-way tie between Australia and the Balkan states of Croatia, Montenegro and Serbia.