Real Madrid striker Cristiano Ronaldo agreed an extraordinary $1 billion (£820 million) lifetime pact with Nike in 2016.

Ronaldo's social media strategy was worth $500 (£410) million to Nike throughout the year thanks to the footballer's unprecedented reach.

One notable Instagram post last summer was worth $5.8 (£4.8) million because of its timing, visibility and interaction it generated.

Four-time Ballon d'Or winner Cristiano Ronaldo is not only a world-renowned goalscorer, but is also one of the most valuable athletes in the world to brands — especially on social media.

Revered as one of the most direct players when he represented Manchester United, the Portuguese striker continued to develop at Real Madrid and has gone on to smash the club's all-time goals record during his eight-year stint at the Estadio Santiago Bernabeu.

He is an athlete who could have excelled at any number of sports, but football is all the richer for his presence.

Ronaldo has won all top honours at club level — from the Premier League in England, La Liga in Spain, and Champions League in Europe — to the 2016 European Championship with Portugal.

Ronaldo's total earnings for 2016 were $88 (£72.2) million

Unprecedented success is typically rewarded with financial gain and, in 2016 alone, Forbes estimated Ronaldo's total earnings for the year to be $88 (£72.2) million — $56 (£45.9) million in salary/winnings and $32 (£26.3) million in endorsements.

Much of that endorsement money will have come from Nike, the global sportswear giant who agreed a $1 billion (£820 million) lifetime pact with Ronaldo in December 2016.

However exorbitant that sum appears, it certainly benefits Nike as much as it does Ronaldo.

Ronaldo "generated $500 (£410) million in value for Nike" from his social media properties in 2016 alone, meaning Nike can recuperate that initial $1 billion (£820 million) investment every two years.

Ronaldo reaches 262 million people through his social media channels. His 120 million followers on Facebook are a living record, while he also has a large-scale reach on Twitter (50 million) and Instagram (92 million).

Last year, Ronaldo published 347 posts that included a Nike logo or a Nike mention and this, in turn, generated 477 million interactions in terms of likes, shares or comments.

One of the most successful posts from a Nike standpoint, according to Forbes, was Ronaldo's summer Instagram message after Portugal defeated France by a 1-0 scoreline in the Euro 2016 final.

A post shared by Cristiano Ronaldo (@cristiano) Jul 13, 2016 at 2:27am PDT

That post (above) featured an illustration of Ronaldo as the iconic Eiffel Tower in Paris and was liked 1.7 million times, with over 12,750 comments. For Nike, this was worth $5.8 (£4.8) million.

Of course Ronaldo's social media worth depends on his success on the pitch, but in 2016 he was an integral part of Real Madrid's push toward the 2016 Champions League title and Portugal's march at the Euros in France — the two greatest trophies a European footballer could have won in that year.

The football great is often compared to FC Barcelona forward Lionel Messi. However, for all of the comparisons, Messi does not come close to offering Adidas the same kind of value.

Messi's social media value for Adidas does not come close to Ronaldo's for Nike

Forbes calculate Messi's social media footprint to be worth $53.5 (£43.9) million to Adidas. This is partly down to "fewer posts" across his networks, which therefore generate fewer interactions, but also because Messi's Argentina were not as successful as Ronaldo's Portugal last year.

With only one point separating Barcelona from Real Madrid at the top of the La Liga table and both teams on course for further progression in the Champions League, Nike and Adidas will likely be more interested in Messi and Ronaldo's season than their fans.