The youngster was out of contract at Manchester United and looked set to join Spurs last summer but the two clubs could not agree a compensation package. Instead, the left-back ended up at Standard Liege but moved to White Hart Lane as soon as the January window opened.
The manager is urging the authorities to look into the matter as the Reds lost out on a sizeable fee for the defender but he accepts that Spurs' actions were not in breach of the current rules.
"We expected that to be honest with you," he replied to MUTV, when asked about the Spurs deal. "How would you put it? To me, I think it's a blatant manipulation of the rules.
"Tottenham did nothing wrong as he went to Standard Liege. They tried to buy him off us and we'd been looking for a certain figure. They wouldn't pay it but asked if they could take him down there on trial and, at that time, he was out of contract in June anyway.
"So he went down on trial and he went to Portugal with them. They then said they weren't prepared to pay the money and, all of a sudden, he signed for Standard Liege.
"We knew immediately and suspected that he would return to Tottenham in January and that's happened. It's a [Spurs chairman] Daniel Levy deal. You know, it's his fingerprints all over it. It's the kind of thing we expected he was going to do."
Sir Alex found it hard to hide his disappointment over the matter and clearly feels the whole situation has been unfair on United, who developed