Pre-tournament favourites Brazil came through a shaky encounter against Belarus to secure their passage to the knock-out stage of the International Volleyball Federation Boys' Under-19 World Championship in Tunis.
The six-time winners squeezed past Belarus 25-16, 19-25, 27-25, 25-17 with Darlan Ferreira scoring 18 points at the Salle Polyvalente Radès.
Despite victory, Brazil are second in Pool A behind Cuba, who secured their last 16 place yesterday.
Hosts Tunisia remain bottom of the pool after losing 27-25, 28-26, 25-10 against Chinese Taipei.
Defending champions Iran were made to work hard for victory in Pool B against rookies Colombia.
Leiner Aponza recorded a record high eight blocks for the South Americans but despite winning the opening set it was Iran who took the victory 25-27, 25-21, 25-17, 25-13.
Czech Republic followed up yesterday's win against Iran with a 25-22, 22-11, 25-22 triumph against Bulgaria.
In Pool C Egypt maintained a perfect start with their fourth win of the tournament.
They defeated Mexico 25-23, 25-23, 25-21 as Japan swept aside Germany 25-14, 25-22, 25-20.
Russia and South Korea are through to the last 16 from Pool D.
Russia bagged their third win by shutting out Nigeria 25-15, 25-14, 25-17 to sit top of the pool.
Korea are in third place behind the United States after thrashing the Dominican Republic 25-17, 25-16, 25-15.
The final pool matches take place tomorrow.