UNDATED (AP) — Former IBF flyweight champion Amnat Ruenroeng of Thailand has won his first bout at an Olympic qualifying tournament in Vargas, Venezuela.

U.S. contenders Cam F. Awesome and Paul Kroll lost their opening bouts, failing to earn spots at the Rio de Janeiro Olympics next month.

The 36-year-old Ruenroeng fought at the Beijing Olympics, falling one win shy of medaling. He is attempting to take advantage of the International Boxing Association's (AIBA) decision to allow pro fighters to compete in Rio.

Ruenroeng won his bout against Germany's Artur Bril, who fights in an AIBA-backed professional league.

Awesome lost a decision to Ecuadorian heavyweight Julio Cesar Castillo Torres, while Kroll lost a 3-0 decision to Germany's Arajik Marutjan in a welterweight bout.

Six American men and two women have qualified for Rio.