Why is it that some great athletes are loved and respected, while others are Cristiano Ronaldo?

Take one example. A couple of weeks ago, Sepp Blatter was asked at the Oxford Union whom he thought was the stronger player: Ronaldo, the 28-year-old striker for Real Madrid and Portugal, or Lionel Messi, his great rival at Barcelona and Argentina. Now, one might have expected the president of Fifa, the international governing body of football, to spot the trick question and park his butt cheeks astride this rather precarious fence.

But no. "Lionel Messi is a good boy who every mother and father would like to have at home," said Blatter. "He's a good man… he's a kind man… and that's what makes him so popular." Blatter did not stop there. He decided that now was the moment to bust out an impersonation of a hoity Ronaldo that he'd been working on behind closed doors and declare: "One has more expenses for the hairdresser than the other." Blatter then signed off: "I like both of them, but I prefer Messi."

It was an extraordinary performance, almost as outrageous and stupefying as the one that Ronaldo himself produced last week. Ronaldo, however, did not require words: in 38 second-half minutes, he blasted a ferocious hat-trick for Portugal against Sweden to secure his country's place in the World Cup finals next summer. While the Swedish crowd chanted "Messi, Messi" – an attempt to rile Ronaldo that famously works; he once extended his middle finger as a riposte – he produced one of the great solo football spectacles.

Actually, Ronaldo did say something. After scoring his second goal, he stopped in his tracks, pointed theatrically to the ground where he stood, and screamed: "I am here!" Even though it makes basically no sense, the statement felt quite revealing: here was someone utterly assured in his own greatness; one man showing his disdain for a supposed team sport. It was exactly the unblushing arrogance that Blatter and others find so offputting about Ronaldo.

This is a recurring issue in any discussion of Ronaldo. When Messi's name comes up, we talk about his sublime gifts on the field, how the ball appears magnetised to his left boot, how the tiny kid with a growth defect has come to dominate world football.

With Ronaldo, it is different. We become distracted by his excessive use of hair product and his predilection for posing in his underwear. We disdain his theatrical nature, whether it is diving for a penalty or his crocodile tears. His chiselled physique smacks of the overdog's privilege, as does the fact that he dates a Russian swimwear model, Irina Shayk. Dubious headlines swirl around him: he was arrested, and cleared, on suspicion of rape in a London hotel in 2005. In 2010, he announced the birth of his son, Cristiano, on his Facebook page; the identity of the mother remains a mystery, but reports suggest he paid a Mexican surrogate £10m for "exclusive guardianship".

Ronaldo was asked once why crowds jeered him. He shot back: "Because I'm rich, handsome and a great player."

Yes, that last bit: he is a great player, and yet bizarrely – because of the other stuff, such as occasionally wearing Speedos – he manages to be an underrated one. His brilliance was obvious on Tuesday night in Stockholm: when he shouted: "I am here!", he was right, wasn't he? He had scored all of Portugal's goals in their 3-2 victory; he also claimed the only goal in the first leg of the match. Even if you believe his reasons for wanting his country to play in the World Cup were entirely self-interested – an extreme argument – you could just as easily recast his performance as an inspiring display of patriotism.

That was certainly the reaction in Portugal. The TV commentators screamed "Obrigado, Cristiano" – "Thank you, Cristiano" – while the daily sports newspaper O Jogo (The Game) surmised: "If it was needed, he'd fly the plane [to Brazil]." After he scored the hat-trick, Ronaldo was buried under a pile of team-mates and Puffa-clad substitutes in a display of carefree exuberance that you would more expect from eight-year-old boys than professional footballers.

Isn't it time we put our prejudices aside and concede that not only is Cristiano Ronaldo truly great, but that he might just be the finest player in the world right now?

Each January, Fifa's Ballon d'Or is awarded to the dominant footballer of the previous 12 months. It is voted for by players, coaches and journalists, and, if that makes it sound as if it has elements of a popularity contest, then the recent results have been unambiguous: since 2009, Messi has won every year, with Ronaldo his runner-up three times.

For all their purported differences, the backgrounds of the two players have similarities. Ronaldo grew up poor, sharing a bedroom with his brother and two sisters on the island of Madeira. His father was a gardener and his mother a cook, and he dropped out of school at 14, after hurling a chair at his teacher and getting expelled. He says he never had toys or Christmas presents and the first time he flew in a plane was in 2003, aged 18, when he signed for Manchester United. As Ronaldo was breaking into the first team in 2005, his father died of a liver condition brought on by drinking.

While Messi might come across as the more humble of the pair – he has only ever played for Barcelona and says he always will – off the field there is again little to separate them. Forbes ranked Ronaldo 9th and Messi 10th on their 2013 list of highest-paid athletes: Ronaldo received $23m from Real Madrid, and $21m in endorsements from Nike, Castrol and Konami; Messi, meanwhile, made the same amount from his sponsors (Adidas, PepsiCo and Electronic Arts among them) but had a salary from Barcelona of $20m. While Ronaldo has posed for Armani, it may be a surprise to learn that Messi has a relationship with the fashion label Dolce & Gabbana and it is not hard to find pictures of him oiled up in figure-hugging white D&G briefs – if you are that way inclined.

In fact, the more you delve into Ronaldo's life, the more you realise how little we actually know about him. When Cristiano Jr was born, the Facebook post read: "No further information will be provided on this subject" – and he has stuck to that, with only rare glimpses of their relationship escaping. After the first leg of Portugal's match against Sweden, Ronaldo was interrupted in the media zone by his three-year-old son asking: "Daddy, can I sleep with you tonight?" He laughed and the moment was actually rather touching.

It is possible we will find out more about Ronaldo when he opens a museum dedicated to himself in Funchal early next year. It will house his medals – he's won four league titles in England and Spain, a Champions League for Manchester United and the Ballon d'Or in 2008 – and it's sure to be popular: Ronaldo has 65 million Facebook fans, more than any other athlete in the world; Messi has 50 million. A bonus is that everyone can now make jokes about the egomaniac who opens a museum dedicated to himself.

After last week, Ronaldo may already be mentally leaving space in the museum for the 2013 Ballon d'Or statue. Voting ends on Friday, although there's a suggestion that he will boycott the ceremony as a payback for Blatter's jibes. Ronaldo is certainly making a compelling case: so far this season, he has scored 32 goals in 20 games, including five hat-tricks. This calendar year, his total is 66 goals in 55 games. It's a run of form that once led ex-Chelsea forward Didier Drogba to describe Ronaldo and Messi as "monsters" for so utterly demolishing modern goal-scoring records.

Ronaldo was asked on Tuesday night if he was playing better than ever. "Perhaps in regards to the amount of goals I'm scoring, this is the best moment of my life," he conceded. "This may be my best season, but I believe that is the case every year. I don't want to talk about the Ballon d'Or any more."

Ronaldo may not yet be loved, but it is impossible now not to respect his talent. Messi, meanwhile, is sidelined for a couple of months after tearing a hamstring and has had to deal with the stain on his reputation of being accused in the Spanish courts of a £3.4m tax fraud – he was fully exonerated last month.

Even if arguments will always rage over their respective merits, everyone can agree that the 2014 World Cup will be more interesting now Ronaldo has confirmed his attendance.