Joseph Diaz Jnr of the United States has beaten Ukraine's Pavlo Ischenko in the opening bout of the bantamweight class.

In a close opening round, it was the 18-year-old who produced the better quality, penetrating Ischenko's tight defence.

Going into the last round, Diaz had a 9-6 lead over his opponent, which forced Ischenko to come out swinging.

However, Diaz's smoother skills prevailed and he forced Ischenko onto the back foot with a string of rapid combinations to the body and head.

Ischenko started walking onto punches and was momentarily stunned by a stiff left hand, but managed to stay on his feet.

Diaz ran out a comfortable 19-9 winner and will now face Lazaro Alvarez of Cuba, who had a first-round bye.