The 2022 continental champions head into their knockouts without winning in three games and take on a side seeking a fourth consecutive win in all competitions.
Match preview
Flamengo were in fine form heading into August, notching four straight wins but Mengao have lost steam since a 2-0 Copa do Brasil last-16 first-leg victory against Palmeiras.
Since that triumph, Tite's men have fired blanks in two matches and failed to secure a win in three heading into Thursday night's match, losing 1-0 to in-form Sao Paulo and their domestic cup second-leg match with Palmeiras by the same score.
The Copa do Brasil loss was not fatal, as they advanced 2-1 on aggregate, but an extension of the team's three-match winless sequence puts the Brazilian side in a precarious position heading into next week's reverse fixture in La Paz.
Despite the discouraging sequence of results, the hosts will hope to extend their Copa Libertadores winning streak in Rio de Janeiro to four having notched three wins without conceding on home soil in the group phase.
One of those games included a 4-0 victory over Thursday's opponents, and a repeat of that result effectively sends them through barring a collapse in La Paz.
Bolivar will hope to avoid losing by a handsome margin against Tite's men in Brazil, keen to enter next week's reverse fixture with a positive outcome in Rio.
The Bolivian outfit got the better of Flamengo by ending Group E atop the standings but face the three-time Libertadores winners in the first knockout round.
A three-game winning streak and their opponent's ongoing dip points to a more favourable outcome than May's result, which puts Flavio Robatto's side in a promising position ahead of the return leg.
Having never lost to Flamengo on home soil, claiming wins in 1983 (3-1), 2014 (1-0) and four months back (2-1), the away side are doubly aware of the importance of stunning Tite's men at the Maracana.
Bolivar notched four points from nine on their travels in the group stage, claiming a 4-0 win over Palestino and a 1-1 draw with Millonarios before the heavy loss to Flamengo which put first place under threat, and they hope that result was an anomaly before taking on their Brazilian opponents.
Flamengo Copa Libertadores form:
D
W
L
L
W
W
Flamengo form (all competitions):
W
W
W
L
L
D
Bolivar Copa Libertadores form:
W
W
W
D
L
W
Team News
Flamengo right-back Guillermo Varela is absent due to a hip issue, joining Everton (Achilles) on the Brazilian side's injury list.
Pedro (five goals) was the only Mengao player to score more than one goal in the group phase, and Tite's men will look to the forward to add to his impressive tally.
Bolivar have no reported injury worries heading into their Libertadores last-16 match with Flamengo, giving Robatto a healthy squad for Thursday night.
Francisco da Costa netted five times in the group stage, but the forward has since been sold, meaning the Bolivian outfit may rely on Bruno Savio (three group-stage goals) to carry attacking responsibility along with Alfio Oviedo, who has netted twice in five since joining the club in July.
Flamengo possible starting lineup:
Rossi; Franca, Bruno, Pereira, Lucas; Pulgar, Allan; Araujo, Arrascaeta, Gerson, Pedro
Bolivar possible starting lineup:
Lampe; Jesus Sagredo, Orihuela, Jose Sagredo, Fernandez; Justiniano, Vaca; Savio, Saucedo, Paz; Oviedo
We say: Flamengo 2-0 Bolivar
Flamengo will be sick of the sight of Palmeiras, having faced their domestic rivals in two of their three-match winless sequence.
Tite's side should return to winning ways against in-form Bolivar on Thursday, keen to put their recent dip behind them and continue an unblemished continental run on home soil.