Hosts Tunisia secured their first victory at the International Volleyball Federation Boys' Under-19 World Championship by edging Belarus.
Tunisia had suffered a straight-sets defeat to Cuba in their opening match yesterday at Salle Polyvalente Radès in Tunis.
They responded in fine fashion against Belarus, who played a five-set match for the second consecutive day.
Tunisia twice took the lead but saw their rivals level the scores on each occasion, leaving the match resting on a deciding set.
The home team took it, to beat their rivals 25-22, 15-25, 25-23, 25-27, 15-12 to earn a first Pool A win.
Cuba top the standings after coming from two sets down to defeat Brazil 23-25, 21-25, 25-22, 25-18, 27-25 to earn a second successive win.
Italy lead Pool B after two straight wins, with their latest being a straight-sets success against the Czech Republic.
Iran moved into second place by winning their first match of the tournament 25-21, 12-25, 25-22, 25-20 against Bulgaria.
Pool C is led by Egypt following a 25-23, 25-16, 21-25, 25-12 win over Argentina, which gave the African team a second victory.
Japan eased to a 25-17, 25-21, 25-12 win over Mexico to move second in the standings.
Russia triumphed in their first match by overcoming the Dominican Republic 25-17, 25-14, 25-17.
They are one of four teams in Pool D to have recorded a victory, as South Korea bounced back from their opening day defeat to Nigeria by beating the United States 25-27, 25-17, 25-20, 25-22.
United States began the tournament with a victory over the Dominican Republic.