On Sunday morning, football fans were left astounded by the publication of Lionel Messi's Barcelona contract.

Spanish newspaper El Mundo controversially revealed the figures and they showed that the Argentine's four-year deal is worth a ridiculous £492m (€555m).

Barcelona have since posted a statement on the matter, declaring on their official website that they will take legal action against El Mundo.

The statement reads: "In view of the information published today in the newspaper El Mundo, in relation to the professional contract signed between FC Barcelona and the player Lionel Messi, the club regrets its publication given that it is a private document governed by the principle of confidentiality between the parties.

"FC Barcelona categorically denies any responsibility for the publication of this document, and will take appropriate legal action against the newspaper El Mundo, for any damage that may be caused as a result of this publication.

"FC Barcelona expresses its absolute support for Lionel Messi, especially in the face of any attempt to discredit his image, and to damage his relationship with the entity where he has worked to become the best player in the world and in football history."

Things are going to get ugly, but there's no getting away from the fact that Messi's contract is the most lucrative in sporting history.

Let's take a look at the other nine mega-deals that make up the top 10, per GQ.

10. Miguel Cabrera (Baseball)

Team: Detroit Tigers

Deal: 8 years, £180.22 million

9. Alex Rodriguez (Baseball)

Team: Texas Rangers

Deal: 10 years, £183.87 million

8. Alex Rodriguez (Baseball)

Team: New York Yankees

Deal: 10 years, £200.65 million

7. Manny Machado (Baseball)

Team: San Diego Padres

Deal: 10 years, £218.89 million

6. Giancarlo Stanton (Baseball)

Team: New York Yankees

Deal: 13 years, £237.14 million

5. Bryce Harper (Baseball)

Team: Philadelphia Phillies

Deal: 12 years, £240.79 million

4. Saul 'Canelo' Alvarez (Boxing)

Team: DAZN

Deal: 5 years, £266.33 million

3. Mike Trout (Baseball)

Team: Los Angeles Angels of Anaheim

Deal: 12 years, £313.75 million

2. Patrick Mahomes (NFL)

Team: Kansas City Chiefs

Deal: 10 years, £367.02 million

1. Lionel Messi (Football)

Team: Barcelona

Deal: 4 years, £491.73 million

Apart from Canelo's deal with DAZN, the rest of the contracts in the top 10 are far longer than Messi's, with seven of them valid for a whole decade or longer.

But despite that, the Argentine's record-breaking contract is worth over £120m more than Mahomes' 10-year deal in second place.

The numbers are outrageous and Sunday's revelations in Spain help explain why Barcelona are struggling so much financially.

Messi's contract, combined with the impact of the Covid-19 pandemic, has left the Spanish giants in a sorry state and reports have shown that the club are currently £1.1 billion in debt, leaving them on the verge of bankruptcy.

The Argentine's deal expires in the summer and it appears there's no way the Catalan side will be able to offer him an extension.