American flyweight Marlen Esparza has defeated Venezuela's Karlha Magliocco to guarantee herself at least a bronze medal.

Esparza made a lightning-fast start and raced into an 8-4 lead after the first round.

She continued to dominate the contest in the second and streatched her lead by two points with some silky boxing.

Despite an improved third round, the Venezuelan was still finding herself completely outboxed.

Magliocco threw everything at Esparza in the final round, but could do nothing to stop the American taking a 24-16 verdict.