Just a few days after leading Barcelona to clinch the treble of La Liga, Copa del Rey and the Champions League, football great Lionel Messi is set to fight a legal battle after a Barcelona court threw out an appeal over allegations of tax fraud.

As reported by The Guardian, the provincial high court in Barcelona said it believed Messi, whether knowingly or not, benefited from a complex network of companies that kept €4.1 million from Spanish tax authorities between 2007 and 2009.

The scheme, which allegedly began way back when the Argentine was a minor, have led to authorities accusing his father, Jorge Horacio Messi, of selling his son's image rights through shell companies in Uruguay, Belize, Switzerland and the UK, as a means to avoid reporting earnings in Spain.

"I have always said it, he had absolutely nothing to do with it, so there is no need to talk about it," Jorge Messi told a Spanish radio show last year. "My lawyers are dealing with this issue so it's something with me and has nothing to do with him."

As noted by the report, last October, a court in Gava ruled that the 27-year-old should face allegations, regardless of whether he was aware of not of the alleged tax fraud.

Messi had made voluntary payments of over €5 million to Spanish tax authorities in the past year to cover the €4.1 million of alleged unpaid taxes plus interest, but despite that, the court said that both he and his father would remain under investigation for three counts of tax fraud.

The Guardian points out that there remains a possibility of an out-of-court settlement, but the state attorney's insistence on pushing forward with the accusations could complicate such a scenario.

Messi has been a resident of Barcelona since 2000, and obtained a Spanish citizenship in 2005.