China completed Pool A at the International Volleyball Federation Men’s Under-21 Championship with a perfect record.
They grabbed their third win in as many games when they sank hosts Bahrain 25-19, 23-25, 25-18, 25-15 at Isa Sports City Hall in Riffa.
Puerto Rico beat Morocco 25-22, 25-21, 34-36, 25-20.
Argentina topped Pool B after overcoming South Korea 20-25, 29-27, 25-22, 25-22, while Cuba condemned Egypt to defeat, prevailing 26-24, 25-20, 21-25, 20-25, 15-9.
Ten-times champions Russia proved themselves the strongest side in Pool C having powered past Tunisia 25-23, 25-17, 25-15.
Iran beat Czech Republic 29-27, 25-18, 26-24.
In Pool D, Italy led the way after seeing off Brazil 25-22, 25-15, 25-18, with Poland defeating Canada 20-25, 25-20, 25-18, 26-24.
The top two sides in each group qualify for Pools E and F, which in turn offer two places each in the semi-finals.
In Pool E are China, Russia, South Korea and Brazil, while in Pool F are Italy, Argentina, Iran and Bahrain.
Second-round games are set to begin on Monday (July 22).