Their conduct appeared to anger United, and manager Sir Alex Ferguson in particular, and the club even reported Real to Fifa over their approaches.
Ramon Calderon, Real president at the time, later attempted to smooth over the apparent rift, saying: "We don't want to get into trouble with them as they are one of the biggest clubs in the world."
However, Calderon - who resigned as Real president in January - has told BBC Radio 5 Live that it was agreed between all parties at the time that Ronaldo would move to the Bernabeu this summer.
"Last season, Manchester United decided not to do it because they thought it was too early," he said. "Everyone involved in the operation agreed to do it this season. That is what I can say."
And that view is supported by Juande Ramos, the former Tottenham boss who managed Real Madrid for six months from December last year.
"Am I surprised (that Ronaldo is joining Real Madrid)? No, because I knew it would happen at some stage," he told 5 Live.
"We already knew that Real Madrid had a pre-contract agreement with Cristiano Ronaldo and that it was only a matter of time.
"I don't know exactly when that agreement was made, but I do know it was in place."
Ronaldo gave little clue about any pre-contract agreement, though, when talking about the move from his holiday base in Los Angeles - to where Madrid officials will fly to conduct a medical before the transfer is completed.
"It's flattering when two of the top teams in the world want you to play for them," said the 2008 Fifa Player of the Year, who has yet to finalise personal terms with Real.
"The deal is historic - £80m is quite a sum of money."
Should, as expected, the deal be concluded by 30 June, Ronaldo would report for training on 10 July ahead of a pre-season training camp in Dublin, Ireland, which will include a friendly.
The La Liga giants will then compete in the Peace Cup in Spain, where their opponents include Aston Villa and Celtic, before heading to Canada, where they will face Toronto FC, and Washington, for a game against DC United.
A United statement on Thursday revealed the record bid was accepted after Ronaldo had "again expressed his desire to leave".
And a spokesman for United's owners, the Glazer family, insisted that the decision to sell Ronaldo was taken solely by manager Sir Alex Ferguson.
The spokesman told the BBC: "It was purely a football decision and had nothing to do with the financial structure of the club."
Fifa president Sepp Blatter said on Friday that he had no problem with the size of the transfer fee, despite the global economic downturn.
"It means that our product is still a good product. If this is the game of the people, they need stars," he said.
"OK, it is a lot of money, but he is performing. In football, we are still in a good market."
However, Uefa president Michel Platini labelled the world record fee as "excessive", adding: "These transfers are a serious challenge to the idea of fairplay and the concept of financial balance in our competitions."
And chief executive of the Professional Footballers' Association, Gordon Taylor, believes football has to be mindful of such large transfer fees given the current financial climate.
"It sets a standard that so many clubs will be unable to compete with - and if you do try to compete (financially with Real Madrid) you are building massive volumes of debt," he said.
"Football isn't immune to the world's problems and, as such, is very vulnerable."
Madrid signed Brazilian Kaka for a reported £56m earlier this week, surpassing the previous world record fee in pounds sterling of £45.6m, which they paid for Zinedine Zidane in 2001.
That deal was sealed by the ambition of returning Real president Florentino Perez, who previously led the Spanish club from 2000 to 2006 - during the famous galacticos era.
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