The agent at the centre of Rangers' aborted attempt to sign Argentine forward Luciano Figueroa has described the Ibrox club as "the most unprofessional I have encountered in 33 years in football".
McLeish watched Figueroa impress against Boca
Eric Manasse was instructed by Rangers' director of football Martin Bain on Wednesday morning to conclude the deal to bring the player to Glasgow.
Manasse maintains that personal terms were virtually agreed with the player, a fee of £2.3m had been agreed and only the method of payment remained unresolved.
But with those negotiations taking place, Manasse says Bain reneged on the deal, withdrawing the offer without explanation.
Bain told the BBC Sport website that this was a case of "a disappointed agent counting his fee before the deal was concluded".
Ironically, the owner of one of the companies that holds a financial interest in the player insists that Rangers' decision to involve Manasse in the deal was partly why the Scottish champions' offer had not been accepted.
"The player is heart-broken," Manasse told the BBC Sport website.
"After the game at the weekend, he had a glass of champagne with Alex McLeish and Martin Bain and was welcomed to the Rangers squad.
"He had his heart set on playing for Rangers and then they pull out, giving me no explanation."
McLeish and Bain had travelled with Manasse to Argentina to see the player score five goals against Boca Juniors.
But Bain told the Rangers' website on Thursday: "Taking everything into consideration, the amount of money involved, the various bids from other parties and the fact that he has just been called up for international duty and is liable to play in next year's Olympics we decided to withdraw our offer."
Spanish club Osasuna have made the only other written offer for the player.
Ricardo Schlieper, whose company Investors Group own a 60% interest in Figueroa, told the BBC Sport website that the Osasuna offer was more attractive to them than the Rangers one.
"There was very little difference between the offers. Both wanted to stagger the payments, which we were not entirely happy with, but really the method of payment is just an excuse for Rangers' offer being rejected," he said.
"The truth is that Rangers' decision to involve other parties meant that the various parties involved became wary of their offer. The Osasuna offer was simpler."
The player's father, Jorge Figueroa, who is also his son's agent, admitted that they were disappointed that the Rangers offer had been withdrawn.
But he added: "The opportunity to play in Spain is an attractive one - they have a stronger league.
"But we will go wherever is best for my son, whether that be Scotland, England, Italy or Spain."
Figueroa was the leading scorer in the Argentine league in the season just ended with 17 goals.
He is currently with the national squad preparing for next Wednesday's game against Uruguay.