Tensions boiled over between the South American sides and both sets of fans in Montevideo
Palmeiras overturned a two-goal deficit to beat Penarol 3-2 but the Copa Libertadores clash was overshadowed by a brawl.
After Willian's second-half brace completed a stunning comeback in Montevideo, tensions boiled over between hosts Penarol and Group 5 leaders Palmeiras, and both sets of fans in the Uruguayan capital.
Former Inter, Galatasaray and Juventus midfielder Felipe Melo - now playing for Palmeiras - could be seen swinging punches before he was chased down the pitch by Penarol players.
One Penarol player picked up a corner flag before police intervened as the violence spilled over into the stands at Estadio Campeon del Siglo.