CAS have today confirmed, however, that they have partially upheld the appeal filed by WADA against the decision issued by the FIFA Appeal Committee and banned the 34-year-old for 14 months, backdated to the start of his six-month ban, meaning he has a further eight months to serve.
Guerrero, Peru's all-time top scorer, was suspended for a year by Federation Internationale de Football Association on December 8 after testing positive for cocaine metabolite benzoylecgonine following Peru's 0-0 draw away to Argentina the previous October, after apparently drinking tea containing the substance.
The CAS chose to increase Mr Guerrero's suspension from 6 to 14 months, starting today, with the period of provisional suspension of 6 months already served by Mr Guerrero being credited against the total period of ineligibility to be served.
But in a unusual turn of events, the Court of Arbitration in Sport (CAS) - of which the President and two board members are Australian and none Peruvian - overruled FIFA's sanction and imposed a 14-month ban.
The court said its judging panel "also accepted that he did not attempt to enhance his performance by ingesting the prohibited substance".
Peru is in Group C with Australia, Denmark and France.
Guerrero, who has denied wrongdoing throughout, had also appealed to CAS to request the ban be annulled altogether.
News of extension of the ban was not well received among Peru fans.
But his solicitors argued that the drug was not a performance-enhancing substance and had been ingested accidentally, by means of "contaminated tea".
Guerrero - of Bayern Munich, Hamburg and Corinthians fame - is Peru's all-time leading goalscorer with a record of 32 strikes in 86 appearances.
Guerrero scored his first goal on Sunday since the suspension, a header in Flamengo's 3-2 defeat at Chapecoense in the Brazilian championship.
This is the second ruling by CAS that has a huge impact on Peru's 2018 World Cup journey.
- Pilot 'sucked out of cockpit window' heroically lands plane after windshield blowout
- Colorado girl seriously injured in bear attack outside home
- Russian Federation 2018: Super Eagles will spring surprise - Izilien
- Tom Wolfe, Author and Creator of 'New Journalism,' Dies at 87
- Fortnite - How To Watch A Match Replay
- Police praise students for one of the "best senior pranks" they've seen
- Flash flood watch issued for Cumberland County Tuesday afternoon
- Watch the Trailer for Upcoming Thriller MILE 22 Starring Mark Wahlberg
- California Regulators Give Go-ahead for Solar Panels on New Homes
- New WhatsApp Group Chat Features Offer More Control And Customization