​Barcelona superstar Neymar has expressed his sympathy to club teammate Lionel Messi after the Argentinian was sentenced to 21 months in jail for tax evasion, Spanish publication Sport reports.

Messi's sentencing follows his decision to retire from international football at the age of 29 after losing in the Copa America final to Chile on penalties. The decision centred around that loss in addition to the previous three major finals losses in the blue and white jersey.

Argentina v Chile: Championship - Copa America Centenario

Neymar, who was himself fined earlier this year for tax fraud, has backed his friend to bounce back from a difficult couple of weeks.

The 24-year-old, who has been on a prolonged absence from the media, said: "Messi is not only my friend, he is also my idol, and I will always support him. I can imagine what he is going through."

His words were even more stirring when he was quizzed over Messi's decision to retire from international football. 

RC Deportivo La Coruna v FC Barcelona - La Liga

He said: "I respect his decisions. But football, without Leo, is not football. It is very difficult to conceive of football without Leo.

"For those who like football, it is impossible to not like what Messi does for Barça and his national team."

Neymar's support of Messi follows the Brazilian's decision to extend his stay at the Catalan giants and Neymar, who was linked with a move to Ligue 1 champions Paris Saint-Germain, spoke of his delight at signing the new five-year deal.

The 24-year-old added, "I am very happy. It is true that there were various proposals, but my wish has always been to stay."

Though he missed international duty with Brazil at Copa America, the former Santos winger will join up with the Brazilian squad for the Rio Olympics, being one of the three over 23s allowed in the squad.

Brazil's Neymar leaves with his silver m