Marquinhos believes the strength of Brazil's squad will allow them to stay at "this level" even as Neymar misses Monday's game against Switzerland through injury.
Brazil impressed in beating Serbia 2-0 in their World Cup opener, but they lost Neymar to an ankle injury following a brutal 80 minutes in which he was fouled nine times.
While the Paris Saint-Germain forward has not been ruled out of the remainder of the tournament, he will not feature in the Selecao's next match.
An injury to Neymar in the 2014 World Cup was followed by Brazil losing 7-1 to Germany, but Marquinhos believes this team – the tournament favourites – can cope with his absence.
"[We are] 100 per cent confident," the defender said.
"We wish we could have Neymar playing with us, we would love to have 26 players fully available, but we are ready and confident we will be able to show our group is strong, well trained, and ready for any difficulties we might face.
"Injuries happen, we must all be aware of these possibilities. We must be wise enough to see everybody has an important role to play, the importance of the ones who were not starting and came in.
"Now we have injuries, it's important that the ones who replace them are ready for the moment so we can play our best. I believe taking into account this talent, we'll be able to keep this level."
Asked how Neymar was feeling, Marquinhos added: "We took some time to digest the situation.
"Right after the game, he was sad. I think that's normal, because he dreamt so much about the World Cup and now he's suffered an injury. As a player, we all understand what he's going through.
"Today, after the tests, the training, the treatment, he's going through physio 24 hours a day, working very hard. It shows how much he wants to be fit and ready.
"We don't know how long it will take. We wish him a speedy recovery and hope he will be fit physically and emotionally very soon."
Marquinhos was also asked about Lionel Messi, another Paris Saint-Germain team-mate, who scored a vital goal for Argentina to keep their World Cup dream alive in what appears likely to be his last finals.
The Albiceleste are Brazil's bitter rivals, but Marquinhos said: "These players... Messi is not just an Argentina player, Cristiano [Ronaldo] not only a Portugal player – they are more than that.
"They are a privilege to football, for all football lovers, so everyone who wants football to evolve and loves football knows how precious they are.
"They do not belong only to their countries. All of us, we enjoy their presence and to see them playing.
"I have played with Messi, Neymar, other great players, and I benefit from their presence. We should all enjoy their presence as much as we can.
"But life goes on, and we know that other generations will come, new great players will come. We have to enjoy the great football as much as we can, keep looking for new players – that's what football is about. Other great players had important moments."