Argentina's Boca Juniors progressed to the Copa Libertadores semifinals on Thursday with a thrilling 4-3 penalty shootout victory over Nacional of Uruguay.

After a 1-1 draw in last week's quarterfinal first leg in Montevideo, the visitors went ahead in the 21st minute at the Bombonera stadium via a Daniel Diaz own goal.

Cristian Pavon equalized in the 73rd minute, but jubilation turned to disbelief for the hosts when the striker was shown a second yellow card for excessively celebrating his goal.

Nacional failed to capitalize on their numerical advantage as 10-man Boca forced the match into penalties.

With the shootout tied at 3-3, Nacional's teenage midfielder Felipe Carballo shot straight at goalkeeper Agustin Orion.

Federico Carrizo then stepped up to coolly convert his spotkick and send the home side's fans into a frenzy.

Boca are aiming to win the Copa Libertadores - Latin America's premier club trophy - for a seventh time, a feat that would see them equal compatriots Independiente with the most titles.