Russia took revenge on Iran by knocking out the defending champions on quarter-finals day at the International Volleyball Federation Boys' Under-19 World Championship in Tunisia.
The Iranians beat Russia in the last final in 2017 in Bahrain, but the tables were turned at the Salle Polyvalente Radès.
As with the clash two years ago, the match was decided in four sets with Russia coming from behind to triumph 21-25, 25-18, 25-20, 25-23.
Roman Murashko led the way for the Russians with 25 points as his country, the third seeds, remained on course for a fourth title and a first since 2013.
Russia have now reached four consecutive semi-finals and blasted in 10 aces against an Iran side who were the tournament's top seeds and hoping for a third title.
Russia will now play Argentina in the semi-finals after the South Americans outlasted Bulgaria over five sets.
Tomas Capogrosso top-scored for the victors with 19 points as an entertaining clash ended 25-19, 21-25, 26-24, 21-25, 15-13.
Bulgaria only squeezed into the knockout phase in fourth place from their group after winning just one game, but then stunned six-time record winners Brazil in the last-16 with a five-set success.
Italy and Egypt will meet in the second semi-final.
The Italians, the 1997 winners, cruised home in straight sets against second seeds Japan, who won bronze in Bahrain.
Tommaso Rinaldi helped himself to 19 points in the 25-17, 25-12, 25-14 success.
Egypt, seeded fifth, also did not drop a set as they beat Belarus 25-21, 25-18, 25-18.
Marawan Elnaggar led the scoring charts for the North Africans with 16 points.
Both semi-finals will be played tomorrow with the final the following day.