Reid said United had opened up their lead by wining matches even when they were not playing well.
"That is why they are 12 points clear and that is the reason I think they will win it.
"I think it is very difficult to retain a title. Everyone wants to beat the champions," added Reid, speaking at St Helens Junior Football Club who are halfway through the Football Pools 90-Day Community Challenge to complete a £50,000 makeover.
"Vincent Kompany and Yaya Toure, two of their best players, haven't been as influential as they were last year.
"They haven't scored enough goals - they scored a lot last season - and that all comes into the equation."