Around 20 Peruvian fans waited outside the courtroom dressed in the national colours and chanting "Paolo is innocent".

Guerrero, who plays his club football for Brazilian side Flamengo, tested positive for benzoylecgonine, the main metabolite of cocaine, following Peru's World Cup qualification match against Argentina in October.

He claims that contaminated tea is the reason behind his positive drugs test.

The 34-year-old subsequently received a one-year ban from FIFA on December 10, backdated to November 3.

This decision meant Peru's record goalscorer, who has 32 goals in 82 international appearances, was set to miss this year's showpiece FIFA event in Russia where Peru are making their first finals appearance since 1982.

FIFA, however, reduced his ban to six months after an appeal, making him eligible for the World Cup.

Two appeals were filed to CAS.

One, by Guerrero himself, sought to reduce the ban further while the other, by the World Anti-Doping Agency, is seeking an extension.

A verdict is likely to be delivered next week.

Peru must name their provisional World Cup squad by May 14.

They are drawn in Group C with France, Denmark and Australia.

"Of course we want his innocence, Paolo has been a neighborhood boy who has come out to play and always with a lot of responsibility and has never been involved in murky things, drugs or anything like that," said Marta Sánchez, one Peruvian national waiting outside the courtroom, to Efe.

"It is a gesture of solidarity to a well-liked Peruvian soccer player, who is a symbol of national sport, a footballer who comes from a humble environment, but who, based on his effort and dedication to sport, has come forward and has come to be world football." another, Jose Villafuerte, was quoted as saying.

The World Cup is due to take place from June 14 to July 15.