The Nerazzurri conceded a late equaliser at the San Siro, with the Brazilian admitting that it was a game he and his teammates should have won.
"We respect sides like Sampdoria, but Inter are a big club and if you want to fight for the Scudetto or finish near the top you can't drop points," he told Inter Channel.
"We've already said that these home games are essential. Unfortunately, it didn't go well against Sampdoria.
"I'm gutted but we're human, you can't always play well. We've still got another 25 games to play, but we mustn't forget that – especially at home – we can't perform like this."
Inter are currently fourth in the Serie A table.