Rangers smashed Aberdeen at Ibrox on Sunday and won 4-0 to move eleven points clear of Celtic at the top of the Scottish Premiership league table.
Celtic dropped more points in a 2-2 draw at Hibernian on Saturday and now have a mountain to climb despite playing two games fewer than Steven Gerrard’s side.
McManus feels the Rangers players are not looking at what Celtic are doing at the moment as they are playing so well and are aware that they will win the league title if they remain consistent from now until the end of the season.
The former Hibernian man said on PLZ Soccer: “I don’t think Rangers are bothering about Celtic’s results at the minute.
“I just think they are getting their heads down, they are concentrating and they are just looking after themselves.
“They are just thinking themselves, we just keep winning games, we keep playing the way we are playing and we win the league this season.”
Celtic will have a chance to cut Rangers’ lead when they travel to Ibrox in January, but McManus stressed that no Bhoys fan is looking forward to the trip given the disparity between the two sides.
“I don’t think there is any Celtic fan who would relish going to Rangers on 2nd January.
“I don’t think anyone would think Celtic are capable of going there and winning with the form both teams are in.”
Rangers won 2-0 against Celtic at Parkhead earlier in the season to lay down an early marker.