Milan, who are currently level on points with Juve at the top of the table, failed to move clear of their rivals this weekend as they were held to a 1-1 draw at home to Bologna.
"We are disappointed because we could not win," Allegri told Sky Sport Italia. "We believed we could win the match and provisionally move to the top of the table.
"But it is true that there are five matches remaining. If Juventus win their match tonight, there is a high chance that they will win the Scudetto, but if they do not, everything will stay just the way it was.
"Nothing is decided yet, also because the second place is not mathematically secure either."
The Rossoneri continue the defence of their title on Wednesday when they host Genoa.