The Catalan giants ran riot in the first leg of this last-16 tie at Camp Nou last week, with Neymar netting a brace as Barca romped to a convincing victory.
However, that fixture - which also saw Luis Suarez, Lionel Messi and Jordi Alba get on the scoresheet - was played against the backdrop of reported unrest within the club.
Luis Enrique came out after the match to play down the mixed reception he received from fans, but Sergio Busquets insists everyone at Barca is pulling in the same direction.
"People usually only know what they are told by the press, but I think everyone has now had a chance to speak," he said. "We just want to be united, to be as one, and for the fans to be behind us."
The uncertainty surrounding the future of Ballon d'Or runner-up Messi has been one of the major contributing factors to the claims of discontent in the Barca ranks, and the Argentina star fuelled speculation by claiming on Monday that he did not know where he would be playing next year.
But Busquets claims he has received assurances that Messi has no plans to make an exit.
"Messi is a very down-to-earth person," he added. "He may be an amazing player but, as he said the other day, he's a squad member like any other.
"He controls his future and he has said he has no intention of leaving and that's very important for us.
"All he was saying [on Monday] was the typical cliche that you never know what might happen in the future."
Barca picked up a morale-boosting 3-1 victory over Atletico Madrid in La Liga on Sunday, getting them back to winning ways in the Spanish top flight after a 1-0 loss at Real Sociedad.
And Busquets hopes to carry that momentum into Thursday's fixture and beyond.
"Beating Atletico was a very positive boost for the team," he added. "It wasn't just the win but also the way we achieved it. It will do us the world of good, but unless we carry on winning then it will all have been for nothing.
"We went 1-0 down to Real in the very first minute . It was bad luck. And they kept it very tight at the back and we couldn't create chances in the first half, although we did in the second.
"Against Atletico we got off to a much better start and were soon winning 1-0. That was a huge reassurance. Everything flowed from that."
Xavi is unlikely to make a return from a calf injury for Barca, while Neymar spent time training alone this week after taking a nasty blow to the ankle against Atleti.
