The creative Pedrinho scored first for the Sao Paulo team in the first half, while substitute Pablo Dyego scored the equalizer for the Rio de Janeiro team eight minutes before the end, in front of over 57,000 fans, setting a new attendance record for Fluminense at the renovated Maracanã stadium.
The match marked the debut this season of experienced coach Oswaldo de Oliveira at the helm of 'Flu', a team he has managed for the third time in his illustrious coaching career, a position he previously held at Corinthians, their opponent on Thursday.
Both teams started the game cautiously after a 0-0 draw in the first leg in Sao Paulo, and in the early minutes Vágner Love had a chance for Corinthians, but it didn't pose much danger, and then the carioca team responded with plays from Igor Juliao and Marcos Paulo.
However, it was Sao Paulo who had the best opportunity with Mateus Vital in the 41st minute, with a shot that required a save from Muriel, Fluminense's goalkeeper and older brother of Álisson, the starter for the 'Canarinha'.
The start of the second half was identical to the first period, with caution prevailing for both teams.
Midfielder Allan attempted a long-range shot to open the scoring, but visiting goalkeeper Cassio was alert and saved it.
In the 54th minute, a lethal counterattack down the left flank by Clayson, who won in speed and passed to Pedrinho, allowed the young creative player from Brazil's pre-Olympic team to score the 0-1 in favor of Corinthians.
Once again, Pedrinho and Danilo Avelar had the opportunity to extend the lead for the Sao Paulo team, while the newly substituted Wéllington Nem and former Paris Saint-Germain player Nené had clear chances to equalize the score.
But the clearest chance up to that point in the match came in the 75th minute when Muriel saved two consecutive shots from Vágner Love and prevented a second goal for his team.
The equalizer for the home team came in the 82nd minute from a free kick by Nené that was well finished with the head by midfielder Pablo Dyego, who had come on in place of creative player Paulo Henrique Ganso.
The goal for 'Tricolor Carioca' was validated by Peruvian referee Diego Haro after consulting VAR.
Corinthians will face Ecuadorian team Independiente del Valle in one of the semi-finals of the continental tournament, winners against their Argentine namesake Independiente de Avellaneda.
The other semi-final features Brazilian team Atlético Mineiro and Argentine team Colón de Santa Fe.
- Technical details:
1. Fluminense: Muriel; Igor Juliao, Nino, Digao, Caio Henrique; Allan, Daniel (m.60, Joao Pedro), Paulo Henrique Ganso (m.77, Pablo Dyego), Nené; Marcos Paulo (m.55, Wéllington Nem) and Yony González.
Coach: Oswaldo de Oliveira.
1. Corinthians: Cassio; Fágner, Manoel, Gil, Danilo Avelar; Gabriel, Júnior Urso, Mateus Vital (m.97, Gustavo), Pedrinho (m.79, Ramiro); Clayson (m.66, Matheus Jesús) and Vágner Love.
Coach: Fabio Carille.
Goals: 0-1, m.54: Pedrinho. 1-1, m.82: Pablo Dyego.
Referee: Peruvian Diego Haro. Booked González, Ganso and Pablo Dyego for the home team, and Gabriel, Gil and Avelar for the visiting team.
Incidents: second leg of the quarterfinals of the Copa Sudamericana played at Maracanã stadium in Rio de Janeiro, with 57,703 spectators in attendance.