La Liga president Javier Tebas made a similar claim past year, with European football's governing body Uefa responding by saying it was not investigating City, who have won the Premier League three times since Sheikh Mansour took over in 2008.
"It is down to us as players to create the atmosphere in there and help the fans", said Walker.
FFP was announced by UEFA in 2010, set to come into force for the 2013/14 season, with clubs threatened with sanctions, including potential Champions League expulsion if they failed to comply.
"When you play against a super team, like tomorrow, if you give an advantage away, it's hard to climb the mountain".
"We do probably lack that a little bit but we have come to terms with that and we have to let our football doing the talking".
The magazine cites a sponsorship deal done with Dubai-based construction company Arabtec, which had been implicated in alleged human rights abuses in a BBC report.
City say they will not be commenting on the claims and that the attempt to damage their reputation is "organised and clear".
"The business and how they handle this sort of situation, I am completely out".
"We work a lot on our defensive organization".
Guardiola insisted he was out of the loop regarding the latest allegations.
City have not commented on the stream of claims beyond referring to a statement they issued last week which read: "We will not be providing any comment on out of context materials purportedly hacked or stolen from City Football Group and Manchester City personnel and associated people".
"We certainly hope Uefa will take the right decisions and enforce Financial Fair Play rules, but we don't have full confidence that they will. In the end we have to focus on what we have to do on the pitch". "UEFA FFP compliance WILL NOT be achieved".
The external company paid City "almost 30m euros" (£26m) and were then reimbursed approximately £11m a year in secret by owner Sheikh Mansour's holding company, Abu Dhabi United Group.
That is the strong and unequivocal message coming out of La Liga following the allegations made against the Premier League champions.
Victory against Shakhtar would put them within one point of qualification with two matches to spare. According to a leaked memo from the club's CEO, Ferran Soriano, the club decided that they needed to fight financial fair play but "do it in a way that is not visible, or we will be pointed out as the global enemies of football".
"But we have learned from that". If we win we are good and accept it, if we lose we accept it's not what we are able to to win.
"That is something I have definitely learned from last season and hopefully we can take it into this season".