Dmitry Bivol defended his WBA light-heavyweight title with a unanimous decision win over Lenin Castillo.

Bivol was too good for Castillo in Chicago, where the judges scored the fight 120-107, 119-108 and 119-108 in favour of the Russian.

In the co-main event prior to Oleksandr Usyk's showdown against Chazz Witherspoon, Bivol comfortably eased past his opponent on Saturday.

Bivol dropped Castillo (20-3-1) to the canvas in the sixth round and he continued to outbox the Dominican fighter for the remainder of the bout.

The 28-year-old Bivol improved to 17-0 with 11 knockouts following the 12-round domination at Wintrust Arena.