Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
The 1977 Copa Libertadores finals was the final two-legged tie to determine the 1977 Copa Libertadores champion. It was contested by Argentine club Boca Juniors and Brazilian club Cruzeiro. The first leg of the tie was played on 6 September at Boca Juniors' home field, La Bombonera, while the second leg was played on 11 September at Cruzeiro's venue, Estadio Mineirão. It was Boca Juniors and Cruzeiro 2nd Copa Libertadores finals.
In the two-leg finals, both finalists won one game each. In the tie-breaking playoff, Boca Juniors won the series through a 5–4 penalty shootout at Montevideo's Estadio Centenario, therefore winning their first Copa Libertadores after the final lost in 1963 v. Santos.
The finals were played over two legs; home and away. The team that accumulated the most points —two for a win, one for a draw, zero for a loss— after the two legs would be crowned the champion. If the two teams tied on points after the second leg, a playoff in a neutral venue would become the next tie-breaker.
Stadiums
Fltr: La Bombonera, Mineirao and Estadio Centenario, venues for the series
Hugo Gatti stops the last penalty kick, allowing Boca Juniors to win Copa Libertadores
Once the playoff extra time finished, Venezuelan referee Vicente Llobregat did not allow Boca Juniors coaching staff to enter the pitch to talk with the men chosen to kick the penalties. Therefore manager Juan Carlos Lorenzo took pen and paper to write the names of players designed to kick, they were Pernía, Tesare, Zanabria, Felman and Mouzo. On the bottom, he wrote the word "abajo" (down) to indicate them where to shoot.
Because of coaching staffs were not allowed to enter the field, one of the ball boys gave the paper to captain Rubén Suñé, then the players ordering themselves to kick the penalties.
Look, I'm gonna be sincere to you because I'm not in the mood for jokes. The ball impacted on me. I moved and the ball impacted on me. Vanderley shot directly to my left side and we won the cup. It was the destiny.
— Hugo Gatti, who stopped the last penalty that allowed Boca Juniors to win the Copa Libertadores for the first time in its history
Boca Juniors (in white shirt), champions
Boca Juniors
Cruzeiro
Fltr: La Bombonera, Mineirao and Estadio Centenario, venues for the series
Defensor Sporting
Libertad
Portuguesa
Deportivo Cali
4'
Boca Juniors
59'
59'
Vanderlei