A mass brawl marred the end of a Copa Libertadores game and Palmeiras claimed their players were deliberately stopped from leaving the pitch by Penarol.
On-loan Inter Milan midfielder Felipe Melo responded with punches when he and Palmeiras keeper Fernando Prass were chased by players from the home team.
Brazilian champions Palmeiras came from 2-0 down to beat the Uruguayans 3-2.
Palmeiras coach Eduardo Baptista said: “When we tried to leave the tunnel was closed and security guards stopped us.”
He added: ” Our own security got us off the field and stopped something worse happening. It’s lamentable. It could have been much worse.”