The two sides played out a goalless draw in the first leg a fortnight ago, meaning that Fluminense still stand a chance of eliminating the defending champions.
Match preview
Despite playing almost the entirety of the second half against 10 men, Flamengo failed to find a way through Fluminense's stubborn backline in the first leg, as the Tricolor battened down the hatches after Felipe Melo's red card.
The Rubro-Negro racked up 18 shots during the previous meeting, while Fluminense registered three attempts on target, but the contest finished goalless following a spirited defensive performance from the home side.
Flamengo booked their place in the last 16 with an 8-2 thrashing of Maringa, with Brazil international Pedro netting four goals in the rout to humiliate the lower-league underdogs.
Since then, Jorge Sampaoli's men have recorded three wins and three draws across all competitions, meaning that Flamengo head into the second leg on a six-game unbeaten run.
Having won seven of their previous nine home matches - suffering a solitary defeat in the process - the Rubro-Negro will be confident of dispatching Fluminense and taking another step towards defending their Copa do Brasil crown.
It is fair to say that Fluminense can count themselves fortunate to have held Flamengo to a goalless draw in the first leg, as Felipe Melo's 52nd-minute sending off looked destined to change to course of the contest.
As it turned out, the Tricolor gave themselves a decent chance of reaching the quarter-finals thanks to their efforts in the previous meeting, although they will need to improve on recent results if they are to overcome Flamengo.
Indeed, Fernando Diniz's men head into the second on a three-game losing run, having suffered league defeats to Botafogo and Corinthians, in addition to a Copa Libertadores loss against Bolivian club The Strongest.
It is also worth noting that Fluminense have failed to score in each of their previous four matches across all competitions, managing a combined total of 10 shots on target during that period.
The Tricolor have reached three Copa do Brasil finals over the years, losing in 1992 and 2005 before triumphing in 2007, while Flamengo have won four and lost four, securing last season's silverware by defeating Corinthians on penalties.
Flamengo Copa do Brasil form:
Flamengo form (all competitions):
L
W
W
W
D
D
Fluminense Copa do Brasil form:
Fluminense form (all competitions):
D
W
W
L
L
L
Team News
Flamengo could be without as many as five players for the second leg, as Bruno Henrique, Everton Ribeiro, Marinho, Matheuzinho and Giorgian de Arrascaeta all missed last weekend's 1-1 draw with Cruzeiro.
Gabriel Barbosa will continue to partner Pedro in attack, while 19-year-old attacking midfielder Matheus Franca is expected to operate just behind the front two.
Veteran centre-back David Luiz will likely come back into Flamengo's starting XI after being rested last time out, with Leo Pereira dropping to the bench.
Believe it or not, Fluminense have more injury doubts than Flamengo, as Alexsander, Gustavo Apis, Jorge, Keno, Marcelo and Marrony all missed Sunday's 2-0 defeat at Corinthians.
With Felipe Melo suspended, Nino is expected to partner Manoel at centre-back, while Andre and Matheus Martinelli will operate in defensive midfield.
Flamengo possible starting lineup:
Cunha; Franca, Bruno, Pereira, Ayrton; Maia, Pulgar, Gerson; Franca; Barbosa, Pedro
Fluminense possible starting lineup:
Fabio; Xavier, Nino, Manoel, Guga; Andre, Martinelli; Lima, Ganso, Arias; Cano
We say: Flamengo 3-0 Fluminense
Given that Fluminense have lost each of their previous four matches while failing to score a single goal, we expect Flamengo to cruise to a comfortable victory at the Maracana, with the reigning Copa do Brasil champions edging closer to defending their title.