United, chasing a record 20th crown, will go eight points clear at the summit if they overcome struggling QPR at Old Trafford on Sunday before Manchester City take on Arsenal at the Emirates Stadium.
City manager Mancini, who has seen his expensively-assembled side lose momentum over the last few weeks, admitted on Thursday that his side will have no chance of catching United if they defeat QPR and his side lose at Arsenal.
But Ferguson, asked about Mancini's comments at a press conference on Friday, refused to be drawn into more mind games with the Italian after their recent verbal sparring.
"I'm not getting into that. I don't need to get into that," Ferguson said.
"We must concentrate on the game ahead and that's Queens Park Rangers. We'll focus on that, not worry about elsewhere."
United are strong favourites to win the title for the fifth time in six seasons after hitting a fine run of form.
Ferguson's side have taken 31 points from the last 33 available since losing at Newcastle on January 4, and are considered to have an easier run-in to rivals City. But the United manager is taking nothing for granted.
"I wouldn't anticipate complacency (from my players) but I do think if you're concentration is not 100 per cent then there will be moments in games like we experienced recently against Fulham," he said.
"Four or five of our player gave the ball away in the space of about five minutes and it created a bit of nervousness.
"We survived that. I made the point that it was good for us to have that because that is an indication of how the games are going to be between now and the end of the season."
QPR, managed by former United star Mark Hughes, are fighting against relegation.
United had to wait until the final 10 minutes before scoring twice to seal victory at relegation-threatened Blackburn on Monday, and Ferguson believes his players will again have to show patience on Sunday.
He added: "It won't be easy because it's another game against a team fighting for survival. They're never easy.
"It wasn't easy on Monday and I don't mind if we have to wait until the final 10 minutes again to win on Sunday.
"QPR have beaten both Liverpool and Arsenal recently and knowing Mark, he's a fighter and his team will fight.
"As much as we're looking forward to the game, it's going to be a hard one."
Ferguson also revealed Portugal winger Nani could be involved after being sidelined for the last five games with an ankle problem.
"He's been training all week. He's such a talented player and makes the squad that bit stronger," said Ferguson.