RIO DE JANEIRO, May 6 (Xinhua) -- Peru captain Paolo Guerrero returned from a six-month doping ban on Sunday as Flamengo defeated Internacional 2-0 in Brazil's Serie A championship.

Guerrero was introduced as a second-half substitute and received a raucous applause from most of the 60,000 fans at the Maracana Stadium.

"I feel like I deserve this after what I've been through in the last six months," Guerrero told reporters. "I'm feeling confident because I'm innocent. I want to play. Football is my life."

Guerrero was given a 12-month ban in December after testing positive for cocaine metabolite benzoylecgonine following Peru's World Cup qualifier against Argentina in Buenos Aires on October 5.

The penalty, backdated to November, was halved by FIFA's appeal committee less than two weeks later.

The 34-year-old striker last week testified before the Court of Arbitration of Sport (CAS) in Switzerland as part of two arbitration procedures which have been referred to the same panel.

In one, Guerrero is attempting to clear his name and, in the other, the World Anti-Doping Agency is seeking to increase the ban to two years.

Guerrero has denied using cocaine or drinking coca tea, claiming he was a victim of food or drink contamination.

CAS said it could deliver a verdict on the cases this week.

Peru have until May 14 to name a provisional squad for their first World Cup since 1982. Ricardo Gareca's side will start their campaign in Russia with a clash against Denmark in Group D on June 16.