"In my opinion they're probably the best Arsenal team of all time and, in their present form, you've got to fancy them to beat United."
Arsenal have appeared in five of the past 11 finals, unlike Millwall, whose semi-final appearance as a Third Division side facing the might of Sunderland in 1937 was the last of three exits at this stage.
In four years as manager at the old Den, Graham led Millwall to promotion to Division Two and to the FA Cup sixth round, where they lost at Luton - a match marred by crowd trouble - after beating Division One sides Chelsea and Leicester.
"I had a great time at Millwall," said Graham, who joined them in 1982 after spells coaching at QPR and Crystal Palace.
"It was my managerial baptism and I probably crammed 10 years of experience into four. It would be a wonderful thing for the club and fans to reach the FA Cup Final.
"I had a great rapport with the fans in those days. There's no doubt that their enthusiasm lifted the team because the old Den was an intimidating place for visiting teams.
"They've got a great chance of winning on Sunday. I know Sunderland are enjoying good form but Millwall have beaten them twice this season so psychologically they'll have the edge."
