Having picked up just one point from their first two games, the Indomitable Lions must win and hope for either a draw, or for Serbia to beat Switzerland by a one-goal margin in the other game in Group G, while Selecao only need a point to finish top.
Match preview
Cameroon kicked off the group stage with a 1-0 defeat to Switzerland, with Breel Embolo scoring the only goal of the game against the country of his birth, in the eighth straight World Cup defeat for the African side.
The Indomitable Lions did create chances, registering as many shots on target as their opponents, but came up just short, meaning they had to get at least a point in their second match, against Serbia.
Despite at one point looking like they were heading for an early exit from the tournament, Rigobert Song's side fought back from a 3-1 deficit to tie the game up at 3-3, after Jean-Charles Castelletto had initially opened the scoring.
Vincent Aboubakar and Eric Maxim Choupo-Moting struck within quick succession in the second half to ensure that Cameroon have something to play for on Friday, showing the determination that will be required if they are to get anything against one of the tournament favourites.
While they will no doubt still be outsiders, Song will be hoping his side may be able to capitalise on playing a Brazil team which may not be as strong as in previous matches, owing to the fact that they are very likely to progress as group winners.
As expected, Brazil have booked their place in the round of 16, winning their first two games at the World Cup for the first time since 2010, in which they reached the quarter-final.
Selecao are yet to concede a goal in the tournament, kicking off with a 2-0 victory against Serbia, in which Tottenham Hotspur striker Richarlison bagged a second-half brace to wrap up the three points.
Following that, Tite's side left it late but again secured a victory, this time against Switzerland, with the goal coming from a perhaps unexpected source, given their array of attacking talent, as Casemiro struck late to seal a 1-0 victory.
The two sides last met in competitive action in the group stage of the 2014 World Cup, in which Brazil emerged 4-1 victors thanks to a Neymar double and additional goals from Fred and Fernandinho.
That scoreline would be more than enough for Selecao on Friday, setting up a round of 16 clash against the team that finishes second in Group H, most likely either Ghana or Uruguay.
Cameroon World Cup form:
L
D
Cameroon form (all competitions):
L
L
D
D
L
D
Brazil World Cup form:
W
W
Brazil form (all competitions):
W
W
W
W
W
W
Team News
Andre Onana will not feature in goal for Cameroon, having been sent home for disciplinary reasons after a disagreement with the manager regarding style of play.
As a result, the more inexperienced Devis Epassy should get the nod between the sticks, as he did in the last match, while Vincent Aboubakar may be brought in to the frontline, having scored from the bench last time out.
Brazil have a number of players unavailable due to injury, with Alex Sandro the latest player to be ruled out, after undergoing a scan regarding the hip issue that forced him off against Switzerland.
In his absence, Alex Telles is likely to come into the team at left-back, having been brought on for the final five minutes last time out.
Key player Neymar is also set to miss out due to an ankle injury which ruled him out of the last game, while another problem in the same area means that Danilo will not be in contention for a place in the backline.
Tite may also choose to rest a few Brazil players as a result of already qualifying for the knockout stages, so Bruno Guimaraes, Gabriel Jesus and Antony could be given some more minutes.
Cameroon possible starting lineup:
Epassy; Fai, Castelletto, Nkoulou, Tolo; Hongla, Anguissa, Kunde; Aboubakar, Choupo-Moting, Toko Ekambi
Brazil possible starting lineup:
Alisson; Militao, Marquinhos, Silva, Telles; Casemiro, Guimaraes, Paqueta; Antony, Jesus, Vinicius Jr
We say: Cameroon 0-2 Brazil
Cameroon are fighting for their World Cup lives in this must-win encounter, but they just do not have the quality to go toe-to-toe with Brazil. When the African side have to commit more men forward to try and win the game, they are likely to be caught on the break and punished by the five-time World Cup winners.