Joseph Diaz Jr. first realized about a decade ago how much he enjoyed boxing when a gym bully picked a sparring match with the young South El Monte boy who would become an Olympian.
"When I went to the boxing gym, there was a guy who already had two years expereince, and he was a bully that used to pick on me," Diaz Jr., who has been coached by his father since he was 11, said. "I was kind of nervous. He tried to be the tough guy. He was like, 'Oh, you think you're tough coming to the boxing gym. Let's spar.'
"I made him bleed, I made him cry. Ever since then I told my dad I love that I could defend myself with boxing. Let's stick to it and see if I can go a long way."
At just 19, Diaz Jr. has already come a long way. He knocked off Ukraine's Pavlo Ishchenko Saturday in a bantamweight (56kg/123 lbs) bout, the first match of the Olympic boxing competition and Diaz's Olympic debut.
The 19-9 decision allowed Diaz Jr. to move on to the round of 16.
"(Ishchenko) had a really tight guard, and so the right hook was the key to get around it," Diaz said.
He will compete Wednesday in a much-anticipated rematch against Cuba's Lazaro Alvarez. The 19-year-old faced Alvarez in a quarterfinal match, losing 19-10, at the 2011 World Championships.
Alvarez would go on to win gold at the World Championships and the Pan American Games.
Round 16 bouts are scheduled to begin Wednesday at 5:30 a.m.