#3 Gareth Bale (£85 million)
Daniel Levy, chairman of Premier League club Tottenham, could be a tough customer to deal with when it comes to transfers. That turned out to be the case back in 2013 when Real Madrid president Florentino Perez targeted the signing of Gareth Bale from the Premier League club.
It was one of that summer's most drawn-out transfers involving lots of twists and turns.
Like so many others, Bale has also seen a move to Real Madrid as his dream. So he felt distraught when Levy stood in the way of his eventual £85m move from the Premier League to La Liga.
He was keen to play in the Champions League, something that wouldn't have been possible at the Premier League club, at least the following year. The temptation to share a dressing room with some of the world's greatest footballers also attracted him to the Santiago Bernabeu.
It was going to be the pinnacle of Bale's football career following his emergence from Southampton. The deal eventually happened and Bale joined Ronaldo and Karim Benzema at the top of Real Madrid's line-up.
Over the course of the next few years, the trio of Bale-Benzema-Cristiano (BBC) went on to impress for Real Madrid. Despite enduring a remarkable fall from grace in recent years, Bale is currently working towards recapturing his best form under former manager Carlo Ancelotti.
#2 Eden Hazard (£103.5 million)
Over the years, Real Madrid have earned a reputation for themselves as a club that gives a player the chance to write his name among the greats of the game.
Hazard left the Premier League to pursue the "next chapter" of his career back in 2019.
In June 2017, Hazard admitted he would be willing to listen to offers from Real Madrid, thus leaving the door open for his eventual departure from the Premier League.
Following the 2018 World Cup he threw his future under further doubt by speaking about his torn state of mind. While he had Chelsea at heart, he was also keen to realize his dream of playing for Real Madrid.
His Premier League exit was eventually sealed for a fee in the region of £103.5 million. Contrary to expectations, Hazard failed to live up to the billings. In the Premier League, Hazard used to play as a left winger, who would often create space and use it to his benefit. Chelsea's entire playing style was based around him.
He would sometimes drop infield and drag opposition defenders along with him. That freed up Chelsea's full-backs, who could then create chances for the strikers. In the process Hazard would draw more fouls.
But that technique failed to work at Real Madrid, often resulting in him picking up injuries and staying sidelined for months. Eventually all his early promises faded and he proved to be one of Real Madrid's biggest misfits.
As things stand, Hazard is a shadow of his former self. Considering his ability, however, it is never too late for him to recapture his menacing form.
#1 Philippe Coutinho (£142 million)
Barcelona were dealt a huge blow when they were forced to part ways with one of their prized assets, Neymar, in the summer of 2017.
The £198m Barcelona pocketed from the deal was used to buy Philippe Coutinho from Premier League side Liverpool for a deal that could rise to £142m. There was a premium added to every deal Barcelona conducted following Neymar's 2017 move as a domino effect.
Following the move, Coutinho said it was incredible to think that he would be living with his idols, "players with a lot of history."
He finished his first season away from the Premier League with 11 goals and five assists.
However, that early promise failed. At Liverpool, Coutinho had emerged as one of the best playmakers in the Premier League.The expectation was that he would do the same with Barcelona.
With the departure of Neymar, the Barcelona midfield lacked creativity and the need was to have someone there who could share the responsibility with Lionel Messi.
While Coutinho has shown sparks of his brilliance, his Barcelona spell has been characterized by inconsistencies.
Ernesto Valverde's insistence on using Coutinho in wider positions also played a crucial role in him losing his early promise.
Initially Coutinho was given more freedom centrally where he could create more chances in his capacity as a playmaker. However, once Valverde switched to the 4-3-3 formation, Coutinho started feeling the heat of bringing the attack from the flanks.
Doubts surround over Coutinho's Barcelona career right now after yet another disappointing campaign last time around. A return to the Premier League hasn't been entirely ruled out.
However, the Brazilian undoubtedly has the potential to turn things around and get back to his best to become a key player for Barcelona in the future.