Stubbs has first-hand experience of why home advantage might not be all that it seems.
He finished on the losing side when Celtic played Rangers in the 1998 Scottish Cup semi-final - despite the tie being played at Parkhead after a ballot because Hampden was being redeveloped.
And, even though United are also unhappy about plans to allocate only 13,000 tickets to their supporters, Stubbs reckons it's who is on the park, not in the stands, that will determine the outcome.
The man who is now coach of Everton's Under-21s said: "The fact it's at Ibrox is obviously an advantage for Rangers.
"But, with the way Jackie's team is playing at the moment, and the way he is going, all he needs to do is focus on his team.
"He will be confident, whichever ground it is going to be at, that he can beat Rangers on that day."
Everton are regular spectators at United games, with full-back Andrew Robertson their main target.
And Stubbs is impressed by the quality McNamara has at his disposal.
"Jackie's got some exciting young players, and there's a lot of talk about them," he said.
"So, whether it's Rangers he is playing, or Celtic, or anyone else, it's a semi-final and he will go into the game thinking he can get a result.
"At the end of the day, they are playing for a place in the final.
"I'd have thought there would be more Rangers fans there. And, if it's a 60/40 split, you go there and you can't worry about things that are not in your hands.
"Focus on what you can dictate, what you can affect. Jackie's team can go there with the confidence that they can beat Rangers, and that's all they need to worry about."