Wintrust Arena, Chicago - All Oleksandr Usyk as he landed 70% of his power punches (88/123) in his heavyweight debut and held veteran Chazz Witherspoon to just 21 total punches landed.

Former undisputed cruiserweight champion Oleksandr Usyk (17-0, 13 KOs) made his heavyweight debut with a seventh round stoppage of late replacement Chazz Witherspoon (38-4, 29 KOs).

Last year, Usyk unified the entire cruiserweight division with a dominating decision win over Murat Gassiev in the final bout of the World Boxing Super Series tournament.

Coming in, Witherspoon had won eight fights in a row, since getting knocked out by Seth Mitchell in 2012.

It was a slow first round, with Usyk feeling out his opponent. Usyk began to land accurate punches in the second, but the action was still pretty slow. Usyk began to get more active in the third, with accurate shots landing. Witherspoon was in the fight and not making it easy at times.

During the sixth, Witherspoon looked gassed and he was taking a lot of punishment in the closing moments. Usyk was trying to let his hands go on Witherspoon at the end of the seventh, with the veteran trying to trade and counter.

At the end of the seventh, Witherspoon was exhausted and did not continue with the fight being waved off.