Riot police had to protect referee Andres Cunha as River Plate beat Gremio with a late penalty in an incredible Copa Libertadores semi-final.
Gonzalo Martinez scored the spot-kick, given via the video assistant referee, in the fifth of 14 added minutes.
Defender Bressan, who conceded the penalty for handball, was sent off as he remonstrated with Cunha, with play held up as Gremio's players protested.
River Plate won the second leg 2-1 and went through on the away goals rule.
The Argentine side, beaten 1-0 at home in the first leg, went further behind when Leo Gomes scored for the Brazilian holders after 35 minutes in Porto Alegre.
River Plate were still two goals behind on aggregate with nine minutes of normal time left, but then Rafael Borre scored.
Uruguayan Cunha then sparked the penalty drama in the 86th minute and was surrounded by Gremio players, with riot police entering the field to protect him during the nine-minute delay that followed before the kick was taken.
Victory for River Plate sets up the possibility of an all-Argentine final against Boca Juniors, who play Palmeiras in Sao Paulo on Wednesday, having won the home leg 2-0.