"Over the last few years, it's been around 89 or 90 points. I think the most has been 92," Sir Alex told Inside United magazine.
"This season it looks like around 85 is the target to aim for."
Sir Alex added: "The big clubs are taking points off each other and sides outside the top three are getting stronger and causing a few upsets. I think 85 will be enough to win it.
"I said in January that it would be a tight finish and that's still the case."