The teams are on a contrasting run of results leading up to this one, with the hosts winless in five straight matches, while their visitors head to Caxias do Sul having come out on top in three consecutive games.
Match preview
Aiming to make up for an early exit last time out, Juventude kicked off their Brazilian Cup journey with an underwhelming goalless stalemate against Iguatu on February 28.
Nonetheless, Jair Ventura's men secured progress into the next stage as a result of the rule which favours away teams going through in the event of a first-round draw.
The Alviverde overcame Paysandu in the subsequent round on March 14 as a Gilberto double set them on their way, before Lucas Barbosa rounded off the scoring, rendering Vinicius Leite's strike inconsequential.
Juventude then took on Internacional in their first two-legged tie of the competition in which a 2-1 win on July 10 was followed by a 1-1 stalemate three days later to secure a 3-2 aggregate triumph.
Since their last cup outing, Juventude have managed just two points from the subsequent four outings, and currently sit 13th in the Brasileiro table, just three points clear of relegation danger.
They will now set out in search of a much-needed advantage to take into next week's second leg against a Fluminense side, who have won just one of the last five meetings between the teams since Thursday's hosts gained promotion to the top flight three years ago.
Due to their seventh-place finish in the league last season, Fluminense did not take part in the opening two rounds of this year's Copa do Brasil.
Mano Menezes's men faced off against Sampaio Correa in their first domestic cup commitment of the season and made light work of the Serie C outfit.
O Time de Guerreiros cruised to a routine 2-0 win in the first leg on May 1 thanks to strikes from David Terans and Jhon Arias, who was also on target alongisde John Kennedy in the second leg to wrap up a 4-0 aggregate victory.
Fluminense's last cup involvement saw them pick up a second of three straight wins at the time, but they would go on to lose seven of their next 10 matches.
However, Thursday's visitors have since won three games on the bounce without conceding and will head into their next outing feeling much better about themselves.
Juventude Copa do Brasil form:
Juventude form (all competitions):
W
D
D
D
L
L
Fluminense Copa do Brasil form:
Fluminense form (all competitions):
D
L
D
W
W
W
Team News
Eighteen-year-old Kaua Elias has scored in three of his last four appearances for Fluminense and is definitely one to keep an eye on.
Thiago Silva has helped the away side to three straight clean sheets since his arrival from Chelsea, but the veteran could be given a breather here.
Brazilian duo Felipe Melo and Marcelo are both expected to miss out in this one, although the former is drawing increasingly closer to a return to action.
Defender Ze Marcos is now eligible to feature once again having served a one-game suspension for his red card in Juventude's defeat to Cruzeiro.
Joao Lucas was hauled off with an injury scare in the first half of the aforementioned game, making him a doubt to play any part for the home side.
Juventude possible starting lineup:
Gabriel; Ewerthon, Sam, Freitas, Inocencio; Goncalves, Jadson, Carlos; Barbosa, Gilberto, Farias
Fluminense possible starting lineup:
Fabio; Barbosa, Carlos, Andrade, Xavier; Ganso, Martinelli, Augusto; Serna, Elias, Marquinhos
We say: Juventude 0-1 Fluminense
While Fluminense have turned a corner of late, they are yet to get going at the top end of the pitch having failed to score two goals or more in a game since the start of June.