City head into the crunch contest at the Etihad Stadium knowing victory would take them back to the top of the Barclays Premier League on goal difference with two games remaining. That would represent a remarkable turnaround from a fortnight ago when, after a crushing loss at Arsenal, City appeared out of contention eight points behind.
Zabaleta told the club's website, www.mcfc.co.uk: "We have to play the same as we play every game. We need to be strong mentally, focus on what we have to do and give it our all. We've got the talent and we've got quality - we've got everything. But behind this the mentality and the attitude for that game has to be more than 100%."
He added: "I'm sure if we put everything into this game, with the quality we've got it can make the difference."
Manager Roberto Mancini claimed the title race was over after the Arsenal loss and has continued to play down their chances since. But with United suffering a shock loss to Wigan and being held to a draw by Everton while City have won three in succession, they are firmly back in the picture.
Argentina international Zabaleta said: "We've never stopped believing in ourselves, but to be honest, after the Arsenal defeat I thought our chance had probably gone.
"We've been five points clear before so we know how it feels, but United losing against Wigan and dropping points at home to Everton shows that in football you have to believe, because you just never know.
"If we have another chance for the title it's because we deserve it. We've kept going and we will continue to do that and see what happens. We know how important this game is. United are the team we want to beat, especially because it gives us the chance to get back to the top."
Zabaleta, 27, will make his 150th City appearance if he plays in the game.
Micah Richards, with whom he has shared right-back duties this season, hopes to overcome a hamstring injury to challenge for the position. Controversial striker Mario Balotelli will also be available after serving a three-match suspension.