Austin MacPhee would not "be given a fair chance" by supporters and the media should he become Hearts manager, Northern Ireland and Stoke boss Michael O'Neill says.
MacPhee, who is caretaker following the sacking of Craig Levein, was O'Neill's assistant for five years.
O'Neill says media criticism of long-haired MacPhee has been "personal".
"I do at times think there is a resistance," he said responding to pundit comments on BBC Radio Scotland.
"Austin is different, there's no doubt about that. He thinks about the game different."
MacPhee has taken a less traditional route to the Scottish Premiership, from being a midfielder in US college football with Wilmington Seahawks, in Romania with Dacia Unirea Brăila and in Japan with Kariya before becoming head coach of amateurs Cupar Hearts.
Having had assistant roles with Cowdenbeath, St Mirrren and Northern Ireland, the 40-year-old joined Hearts in 2016 as assistant to Ian Cathro, who had himself taken a unique route by heading Dundee United's youth academy at the age of 22.
"I think Ian Cathro was in a similar mould and I think a lot of the criticism of Ian in the media was unfair," O'Neill told BBC Sportsound.
"Ian is now working in the Premier League with Wolves and you don't get to that level without a good knowledge of the game. I think we are too quick to judge people if they are not in the scene of Scottish football."
O'Neill pointed out that, as Levein was also director of football, Hearts are in a difficult position of having to fill both roles when ideally the director should be appointing the manager and suggested that MacPhee might be "more suited" to the upstairs role.
"Because I don't think he would be given a fair chance as head coach given the water that's gone under the bridge and what happened with Ian," he said.
"I understand people's opinions about whether he is ready or not to be a number one, but regardless of whether he is the manager or not, I think Hearts would be very silly to think he does not have a value to the club."
MacPhee is keen to take the Hearts job permanently and, although O'Neill suggests that owner Ann Budge might want someone with more experience to "appease" the fans, the Stoke boss thinks he should not be discounted because he was assistant to two managers who have been sacked.
"What he's brought to me is a high level of knowledge on the opposition, a creative way to train, which is particularly important in international football, when you have a short time to prepare, and he's been creative in how he brought information to the players and how it has been communicated to the players," he said.
"We have players like Jonny Evans, Steven Davis and Craig Cathcart who have played at the highest level in the Premier League and he has a lot of respect from those players. Austin has a good way of looking at the game and has a lot of initiatives that are extremely valuable to Hearts."
Questions over selection and ambitions
Former Hearts midfielder Derek Ferguson on Sportsound
My criticism on Saturday was on the back of the semi-final game against Rangers, where I personally thought he got his team selection wrong.
I thought that maybe Austin was trying to be a little too clever for his own good and they got found out.
Former Aberdeen and Scotland defender Willie Miller on Sportsound
My main criticism was what he said before the game against St Mirren and it sounded to me like he had ambitions of getting to the group stage of the Europa League.
He's got a great result on Saturday, which is fabulous for him, but when you are in a relegation battle, you shouldn't be talking about the Europa League.
I would have been more comfortable with Austin's words if he had concentrated on the plight that Hearts are in and the job he has to get out of that situation.
All he can do is win matches and take it form there, but if Ann Budge is saying she needs someone who is experienced and high-profile, that's not Austin MacPhee.