Firmino came off the bench for the closing stages of Brazil's 1-1 draw with Switzerland in Group E on Sunday, while Mane is expected to make his World Cup debut on Tuesday against Poland.
Both have been in deadly form at club level during the 2017-18 season, in which Firmino scored 15 Premier League goals alongside Mane's total of 10, and they will be aiming to transfer those performances onto the international stage.
While Firmino is yet to establish himself as a regular starter for Brazil, finding himself behind Manchester City forward Gabriel Jesus in Tite's pecking order for the Selecao's opening game, Mane believes the work-rate of his Liverpool team-mate makes him a special player.
"He's a hard worker and an incredible player," the Senegal international was quoted as saying by Liverpool's website.
"He can see in his eye and what he's doing all the time on the pitch, working for the team like a defender and he's a striker!
"This is special for him and it makes him a very, very, very important player for us."
10 - Liverpool are the first team in history to see three players score 10+ goals in a single Champions League season (Salah 10, Firmino 10, Mané 10). Trio. #RMALIV pic.twitter.com/L95krx8QXO — OptaJoe (@OptaJoe) May 26, 2018
With Brazil failing to win their opening game at a World Cup for the first time since 1978, Tite's side are searching for improvements in their next group-stage matches against Costa Rica and Serbia.
If Firmino manages to add to his six Brazil goals, it is likely the 26-year-old will celebrate with dancing - and Mane added that his Liverpool team-mate is always trying to get him involved in his celebrations.
"Roberto is someone who likes dancing all the time and he always forces me to dance with him," he said.
"I try my best but I'm not as good as him! He was talking to me, saying 'why don't you dance like we said all the time?!' and I said: 'Hey Bobby, I'm shy, I can't dance like you!'
"He said 'come on my friend, we have to do it!' and we enjoy each one, so why not!"