Luis Nery’s exceptional victory over Shinsuke Yamanaka is now under review following a positive test result prior to their contest last week.
The Mexican scored a career-best win on August 15 at Yamanaka’s home in Japan and was celebrated a few days later in a homecoming press conference.
A report from the World Boxing Council’s Clean Boxing Program has since cast a huge shadow on Nery’s win ahead of a full investigation into the findings.
“The WBC has been notified by VADA of an adverse finding from an out of competition sample taken from WBC bantamweight champion Luis Nery,” said a WBC statement.
“The substance is Zilpaterol which is very similar to Clembuterol. The adverse finding came from the testing leading to his world title fight versus Shinsuke Yamanaka which took place in Japan on August 15.
“The WBC Clean Boxing Program will begin the process according to its protocol and will provide additional information during the process.”
Nery, who is just 22 years old, pushed his record to 24-0 with the shock win, and in the process ended Yamanaka’s hopes of breaking a Japanese record of world title defenses.
Yamanaka, 34, put in an immediate request for a rematch following what was his first ever loss, but could now be reinstated – or at the very least contest the vacant belt.