Bolivian club Wilstermann upstaged powerhouse River Plate 3-0 to take control of their Copa Libertadores quarter-final clash.
Edward Zenteno, Gilbert Alvarez and Cristhian Machado were on target as the Bolivians won Thursday's first leg in Cochabamba.
River has history in South America's premier club competition, having won it on three occasions – its most recent success coming in 2015.
However, the Argentinian club came unstuck against 1981 semi-finalist Wilstermann at Estadio Felix Capriles.
It took five minutes for Wilstermann to take the lead through Zenteno, who volleyed powerfully from Marcelo Bergese's corner.
Alvarez doubled the lead six minutes into the second half when he latched onto Cristian Chavez's cross.
The comprehensive victory was sealed by Machado with eight minutes remaining as Wilstermann extended its unbeaten streak to 10 matches in all competitions.
Wilstermann travel to River for the return leg on 21 September.