But the 39-year-old feels the way he has dealt with the supporters' doubts has strengthened his confidence in taking on the role.
Courts has been confirmed as United's new boss after stepping up from his previous position as head of tactical performance with the club's academy.
Courts takes over from Micky Mellon, who left Tannadice after one season in charge before returning to Tranmere.
His previous management experience was with Kelty Hearts who he left in the Lowland League in 2018 and will face in the Premier Sports Cup next month.
The former Livingston, Cowdenbeath and East Fife player did not apply for the job and did not expect to be in the frame but feels he has the mentality to succeed.
"When the previous manager departed it was a bit of a shock for everyone internally," Courts told United's DUTV.
"When I got the invitation to speak to the club I was pleasantly surprised, albeit quite optimistic because I felt I was ready for the challenge to at least be interviewed.
"The fans are probably in a very similar frame of mind to me just now because the reason I didn't apply for this job was because I had no real frame of reference, that an academy coach or a coach who started in a different part of the pyramid, could actually be a head coach of a club like this.
"The fans were probably assuming the club would go down a more experienced route.
"But they are getting a very experienced manager, one who has a proven capability of winning, developing players and also being open and receptive to giving opportunities to youngsters too."
Courts, who will be assisted by former Hearts and Livingston coach Liam Fox, aims to use the fans' passion to his advantage.
"There has been a little bit of energy online surrounding the appointment but I want to harness that energy," he said.
"I empathise with the fans because they don't have that frame of reference and they only want to protect the interests of the club.
"I do actually think they have a point. I think there are some similarities between how I was feeling on potentially getting this job and how the fans were feeling, because there was no real point of reference. I have never looked at a club of this size and stature appointing internally.
“But what I have tried to do is harness that as a positive, because it has been a good challenge to my temperament and my mentality.”
Sporting director Tony Asghar insists Courts will be a positive force for the club's experienced players as well as the youngsters.
"We have been extremely impressed by Tam since he joined the club 18 months ago and I believe he is an excellent appointment with a tremendous skill-set that can only enhance what we have already in place," Asghar said on United's website.
"He has demonstrated an incredible work ethic, a real passion for the club and the players and a confidence in his own abilities to step up and take charge of the first team.
"The senior players within the club, as well as our younger players, will benefit from working under Tam and this will be an integral part of achieving success in our objectives."