Following last Sunday's defeat to Real Sociedad, in which Lionel Messi and Neymar were benched, claims were made in Spanish press that there had been a fall-out between the coach and his players.
Since then Barca have hammered Elche 5-0 to all but ensure their Copa del Rey progression before seeing off La Liga champions Atletico Madrid 3-1 on Sunday.
After a victory that put second-placed Barca three points clear of the defending champions, Mascherano hit out at the suggestions in the press and stressed the importance of the win.
"I think we played a great game against a strong rival that makes you compete to the maximum," the Argentina international told Barca's official website.
"I don't know what people out there are saying about us, but these are three very important points.
"Beating Atletico Madrid is great but next week we have to win again or these three points are meaningless.
"Everything that was in the media this week was a complete fabrication, all falsehoods."
Barca play the second leg of their last-16 clash with Elche on Wednesday and, with a sizeable advantage in hand, Luis Enrique may opt to rest some of his senior players.
However, Mascherano warned his team-mates will take the game seriously regardless of who is selected.
"I think it's important to keep winning, whoever has to play so we can win games," he added.
"We're the ones out there defending the shield so we have to look out for ourselves."
