Messi is rightfully the world's most lauded and admired footballer as, on the pitch, he has achieved feats barely plausible in the modern game, such as his 91-goal haul in the calendar year of 2012 that overhauled German Gerd Mueller's 40-year-old European record.
However, in contrast to many of his contemporaries, it is his camera-shy, humble attitude away from the pitch that has allowed many to warm to him.
And that image is precisely why Wednesday's news came as such a surprise.
Messi, who is accused along with his father Jorge Horacio, strongly denied the allegations via his Facebook page, saying that he had not even been informed by the tax authorities of the complaint.
"We have just known through the media about the claim filed by the Spanish tax authorities. We are surprised about those news, because we have never committed any infringement," he said.
Ironically, given his squeaky clean image, it appears to be how he has handled money earned from image rights that the authorities are challenging.
They claim that the player and his father used tax havens in Belize and Uruguay to avoid paying tax on image rights from a number of the player's huge endorsement deals.
The pair are accused of defrauding the state of taxes related to that income in 2006, 2007, 2008 and 2009, the year the Argentine won the first of his four Ballons d'Or.
Since that time Messi's exceptional performances on the field have seen his value as a marketable commodity soar.
He scored in both the Champions League finals of 2009 and 2011 as Barca overcame Manchester United to claim their third and fourth European crowns respectively.
Meanwhile, his individual goalscoring feats have become legendary.
His 91 goals in 2012 helped him smash Real Madrid rival Cristiano Ronaldo's previous record of 40 goals in a La Liga season, as Messi registered 50 in the league and equalled the record number of goals in a single Champions League campaign with 14.
Those feats allied to the winning of his fourth Ballon d'Or in January saw him move up one place in this year's Forbes list of highest-paid athletes to 10th with an annual income of $21 million from endorsements alone.
Off the field, things appeared to be going very smoothly for Messi too as his long-term girlfriend Antonella Roccuzzo gave birth to their first child, Thiago, in early November.
And the 25-year-old's down-to-earth image was evidenced once more when he carried his seven-month old son around the Camp Nou field as Barca celebrated winning their fourth Spanish title in five years last month.
However, this latest news rounds off a frustrating few weeks for the world's best player as his brilliance on the field has also been tempered by
A hamstring problem forced him to watch on from the sidelines as Bayern Munich hammered Barca 3–0 in the second-league of their Champions League semi-final to seal a record 7–0 aggregate defeat for the Catalans.
And a recurrence of the injury against Atletico Madrid early in May forced him to miss Barca's last four league games of the campaign.
He returned just in time to take part in Argentina's two World Cup qualifiers against Colombia and Ecuador in the past week, but again his lack of fitness reduced his role to merely that of a substitute for the last half-hour of both matches as La Albiceleste could only manage two draws.
As a result, they are still a few points short of mathematically sealing their place at next year's World Cup in Brazil.
And on the very day on which he was due to start his holidays after an exhausting 10-month long season, the Argentine star now must face up to the first serious scandal to affect his career.