On loan from Milan, Brazil international Robinho struck twice in the first half of a 3-2 win at Botafogo in the quarter-finals.
A three-goal first half set up Santos, who were reduced to 10 men in the 84th minute when Robinho picked up his second yellow card.
Robinho was gifted his opener in the 25th minute after an awful turnover of possession by Botafogo just outside their own area led to the forward being played through by Leandro Damiao, before he finished neatly.
Botafogo equalised almost immediately as Gabriel curled a wonderful effort into the top corner from just inside the area after taking a pass from Wallyson.
Robinho restored Santos' lead in the 29th minute as he completed a team move with another low, powerful finish.
Geuvanio struck with an individual effort just before half-time, with his 20-yard shot sneaking under Botafogo goalkeeper Jefferson.
Pablo Zeballos tapped in a Dankler cross in the 57th minute to give Botafogo hope.
In a blow to Santos, Robinho picked up two yellow cards within five minutes of one another to be sent off.
Serie B sides ABC and America RN both suffered one-goal losses.
Leo's 79th-minute header saw Cruzeiro edge visitors ABC 1-0, while America RN were beaten 1-0 at home to Flamengo.
Corinthians are well-placed to advance after a 2-0 victory at home to Atletico Mineiro.
