Spain beat Brazil and the United States saw off Uruguay to reach the Under-20 World Cup quarter-finals along with Austria and the Czech Republic on Wednesday.
Spain came from behind to secure a 4-2 extra-time victory over Brazil in a thrilling encounter in Burnaby.
Goals from Leandro Lima and Alexandre Pato put Brazil 2-1 up but Spain equalised six minutes before the end of normal time when Javi Garcia floated in a free kick with the defence sleeping.
Bueno took Spain towards the last eight 12 minutes into extra-time with a stooping header after a fine run and cross from the impressive Diego Capel.
Brazil struggled after Lima was sent off and Spain sealed victory in the final minute with a goal from Adrian Lopez.
Uruguay looked to have finished off the Americans in Toronto when Edinson Cavani's header was parried out by US keeper Brian Perk and Luis Suarez drove home the loose ball.
But the U.S. forced the game into extra-time after Uruguay defender Mathias Cardaccio slid Danny Szetela's cross into his own net.
The winner came in the second period of extra-time, when the Uruguay defence failed to deal with a corner and Michael Bradley slammed the ball in from close range.
The game ended with ugly scenes as players from both sides confronted each other on the pitch and coaches and officials were forced to intervene.
The US will meet Austria, who ended Gambia's ambitions with a 2-1 victory in Edmonton thanks to substitute Erwin Hoffer's 81st-minute winner.
Despite having midfielder Seiya Fujita sent off in the first minute, Japan went 2-0 up against the Czech Republic thanks to goals from Tomoaki Makino and Yasuhito Morishima but let their advantage slip as penalties from Ondrej Kudela and Jakub Mares brought the Czechs level.
With neither side scoring in extra-time the match was decided by a penalty shootout which the Czechs won 4-3.