Meanwhile, their opponents still have plenty to play for, currently finding themselves in a battle for the final qualification spots with Sunday their final opportunity to pick up points.
Match preview
Ecuador find themselves on the edge of dropping out of the Copa America at the group stage, as they face the most daunting test of the group having only collected two points so far.
They started the campaign with a 1-0 defeat at the hands of Colombia, as Edwin Cardona netted the only goal of the game on the stroke of half time.
Gustavo Alfaro's men then looked set to bounce back with a 2-1 win over Venezuela, but they would be held to a draw by a late equaliser.
Ecuador took the lead on two separate occasions through Ayrton Preciado and Gonzalo Plata, and the latter appeared to have proved the difference until Ronald Hernandez found the net in the 91st minute for Venezuela to force La Tricolor to share the points.
Alfaro's side then played out another 2-2 draw on Wednesday, as they again gave up a lead in their clash with Peru.
A Renato Tapia own goal and an Ayrton Preciado goal on the stroke of half time saw them go into the break with a two-goal lead, but it did not take Peru long to get back on level terms as Gianluca Lapadula pulled a goal back before Andre Carrillo netted the equaliser in the 54th minute.
Having led in their last two games before being held to a point on both occasions, La Tricolor will be disappointed that they sit where they do in the group, now majorly threatened by elimination.
They go into the final game of the group stage to face their toughest test yet, and Alfaro's men know that they may need a result to remain ahead of Venezuela, who only trail on goal difference and have a slightly more favourable final game against Peru.
Host nation Brazil come into the game with no real need for a result in terms of their qualification bid, but will be hoping for another win to finish a perfect group campaign and build more momentum for the quarter-finals nonetheless.
They are somewhat lucky to still boast a perfect record though, having scraped past Colombia in their last group outing.
Their opponents led for the majority of the game thanks to Luis Diaz's stunning 10th-minute opener, and it took until the 78th minute for Brazil to equalise through Roberto Firmino, before Casemiro headed in a corner in the 10th minute of added time to snatch all three points for the Selecao.
That came after much more comfortable victories over Venezuela and Peru, winning 3-0 and 4-0 respectively, as Marquinhos, Neymar and Gabriel Barbosa got on the scoresheet against Venezuela before Neymar again found the net alongside Alex Sandro, Everton Ribeiro and Richarlison in the following match.
Having now won their last 10 games in all competitions, pressure has never been so high on the Selecao to retain the Copa America title on home soil, and they will hope for another victory to round off a strong group stage and continue to build momentum going into the knockout stage.
Ecuador Copa America form:
Ecuador form (all competitions):
Brazil Copa America form:
Brazil form (all competitions):
Team News
Given their need for a result against a dangerous Brazil side, Ecuador may be forced to move to a more cautious system, with Xavier Arreaga expected to come in to form a back five.
Winger Ayrton Preciado will be a key man going forward, having found the net in both of the last two Copa America games.
He will support striker Leonardo Campana, who remains in search of his first international goal.
With an important quarter-final clash looming, Brazil are expected to continue to rotate their squad, having made several changes for each group game so far.
With each of the three goalkeepers in the squad having played one group gam, Manchester City's Ederson and Liverpool's Alisson will likely battle for the spot for the remainder of the tournament, with a chance to earn their place for the quarter-finals if they can step up on Sunday.
Tite should revert back to the centre-back pairing of Eder Militao and Marquinhos, giving 36-year-old Thiago Silva a rest after two games in quick succession for the Chelsea defender.
Neymar will remain a prominent man in the front line, having hit two goals and two assists in their three games so far.
Ecuador possible starting lineup:
Galindez; Angelo Preciado, Arreaga, Hincapie, Arboleda, Estupinan; Mena, Mendez, Caicedo, Ayrton Preciado; Campana
Brazil possible starting lineup:
Alisson; Danilo, Marquinhos, Militao, Sandro; Everton, Casemiro, Fabinho, Richarlison; Neymar, Firmino
We say: Ecuador 0-3 Brazil
Despite having a far greater need for a result, Ecuador should fall short to a strong Brazil side who find themselves in a good run of form.
The Selecao will look to continue their momentum and head into the quarter-finals on the back of four group wins, and they have more than enough in their locker to get past Alfaro's men.