Manchester United beat a host of European giants to Cristiano Ronaldo in 2003.
It has now emerged that Liverpool thought they had a £4million deal in place.
Reds boss Gerard Houllier went to see Ronaldo play for Portugal's Under 20 side.
Frenchman was shocked when the winger joined Manchester United for £12.2m.
Ronaldo won the first of his Ballon d'Or awards at Old Trafford plus nine trophies.
Liverpool were confident they had beaten Europe's biggest clubs to the signing of Cristiano Ronaldo in 2003 - only for fierce rivals Manchester United to gazump them.
Sir Alex Ferguson swooped for the Sporting Lisbon starlet in August of that year, paying £12.2million to sign him ahead of the likes of Barcelona, Juventus and Arsenal.
But it has now emerged that Liverpool thought they had the basis of a deal in place to sign Ronaldo - then one of the hottest teenagers on the planet - for just £4million.
The Athletic have revealed details of the Reds' failed move, which began after they watched the future five-time Ballon d'Or winner star in a game against Porto.
After the match, Liverpool's assistant manager, Phil Thompson, went out for dinner in the Portuguese city with football agent Tony Henry. Ronaldo's price-tag was the subject of conversation.
'I can still remember Tony's exact words,' Thompson told The Athletic. 'It was all very nice and relaxed. "It's £4 million and it can be paid over the four years of his contract, so £1 million a year".
'That seemed very reasonable. Then I asked about the salary and Tony told me it was £1 million a year, net.'
Despite having reservations over Ronaldo's salary demands - he was just 18 at the time - Liverpool were still keen to get a deal over the line for what they saw as a 'great talent'.
They believed they had an agreement in place to sign the winger for £4m, although personal terms had not yet been thrashed out.
Liverpool boss Gerard Houllier also went to watch Ronaldo in action himself, travelling to the Toulon tournament to see him play for Portugal's Under 20 side.
But then everything changed. Out of the blue, from Liverpool's perspective at least, Ronaldo was off to Manchester United for treble the fee they had agreed to pay.
Thompson added: 'On the Tuesday morning, we were having lunch at the training ground and it came up on the yellow strap on Sky Sports, "Manchester United have signed Cristiano Ronaldo for £12.2 million".
'Gerard and myself almost choked on our food. I can remember Gerard jumping up and saying, "What the hell has gone on there?".
Liverpool were left to rue their failure to land Ronaldo, who quickly developed into one of the world's best players during his six year spell at Old Trafford.
After winning three Premier League titles, a Champions League and his first Ballon d'Or award, he departed for Real Madrid in 2009 in what was then a world record £80m transfer.
Liverpool weren't the only Premier League club who almost signed Ronaldo before Manchester United.
Earlier this week, Arsene Wenger revealed that the Portuguese starlet 'had the shirt' at Arsenal months before he sealed a move to Old Trafford.
When asked by the Guardian for his biggest transfer regrets, the Frenchman said: 'Oof! I would say there is not one player, there are 50!
'On the other hand, maybe the closest [to that] was Cristiano Ronaldo, when he signed for Man United.
'We had an agreement with Sporting and Man United took Carlos Queiroz as assistant coach, and they just outbid us quickly and took Ronaldo, but we had an agreement basically. He had the shirt of Arsenal, I had lunch with him and his mother at the training ground!
'It's one example but there were so many. The history of a big club is full of missed great players!'