And he revealed he will continue to fight to get his dramatic project carried out.
John McAslan found out on Monday that his vision for the square had been selected by judges from a short list of six.
But just minutes later, he read online that Mr Matheson had announced it would not be going ahead.
The council boss insisted the public was not in favour of a radial redesign of the square so it would get only a relative minor spruce up instead.
Mr McAslan, whose firm McAslan and Partners is based in London, has contacted Mr Matheson asking for a face to face meeting next week.
He said: "I want to meet Councillor Matheson and get to the bottom of this decision.
"I was born in Glasgow and I want to take this as far as I reasonably can to make something happen.
"Mr Matheson should have had the good grace to give us that opportunity.
"I have the determination to build the scheme but if at some point the door gets firmly closed and cannot be reopened we will have to reconsider.
Mr McAslan believes when his scheme won, there should have been a chance to explain it in detail to the public.
He said: "There should have been a public meeting where the designer presented the idea and the public raised their concerns.
"At the end of that everyone feels their views have been listened to.
"For goodness sake, give us a chance to listen to the people of Glasgow."
Mr McAslan praised everyone involved in the design competition including council staff and the panel of judges.
But he said: "The process has been let down by the subsequent decision by Councillor Matheson – you just don't behave in that way.
"He probably didn't get the scheme he wanted and used his position to manipulate his way out of it."
A council spokesman: "Under the procurement process for the design contest, the jury had to choose a winner.
"The next stage of the process was for the council to decide to award the contract to the winning company.
"However, that recommendation will now not be put before councillors because it has become clear that there is no public support for a radical redesign of the square."