Uruguay's Nacional overcame a outbreak of mumps in their team to knock defending champions Boca Juniors out of the Copa Sudamericana.
Seventeen-year-old Rodrigo Tapia scored after 30 seconds of his professional debut as Colo Colo beat Cobreloa 2-0 in Chile at the weekend.
Ecuador need a point at home to Uruguay on Saturday to clinch their place at the 2006 World Cup finals. Paraguay can also qualify if they win or draw in Venezuela and other results go their way.
Brazil striker Adriano scored a hat-trick in a 5-0 win over Chile on Sunday to guarantee the world champions a place at next year's finals while Uruguay sealed a dramatic 3-2 win over Colombia.
Colombia and Uruguay, two teams in crisis, meet in a match neither can afford to lose while Argentina have a chance to regain the lead from Brazil in South America's World Cup qualifying competition this weekend.
Arch-rivals Argentina and Uruguay were thrown together when the draw for this year's Copa America was made in Peru on Monday.