A red card for Sao Paulo's Maicon 17 minutes from time opened the door for Atletico Nacional to secure a decisive 2-0 away win in the first leg of their Copa Libertadores semifinal.
The match seemed destined for a scoreless draw before the defender was sent to the stands for violent conduct. The visiting Colombian side then took full advantage of their extra man, with debutant Miguel Borja scoring a brace in the final 10 minutes.
The 23-year-old, who joined from Atletico from Cortulua, turned in Macnelly Torres' excellent pass in the 82nd minute, before doubling his tally with a superb back heel six minutes later.
Atletico Nacional now hold a huge advantage ahead of next week's return leg in Medellin.