Joseph Parker stopped Martin Bakole in round two of their Riyadh bout to retain his interim WBO heavyweight title.
The New Zealand boxer was initially set to face IBF heavyweight champion Daniel Dubois, but the Briton pulled out of the fight on Thursday, citing illness.
Up stepped 33-year-old Congolese fighter Bakole, who got off to a sluggish start but looked more assured when he landed a big hit to end round one.
Bakole's evening came to a quick conclusion, however, after Parker sent him flying with a huge right hook to the head for the swift technical knockout.
The result means Parker becomes the WBO mandatory challenger for full title-holder Oleksandr Usyk.
Meanwhile, Dmitry Bivol saw off Russian compatriot Artur Beterbiev to be crowned the undisputed light-heavyweight world champion.
Bivol, 34, reversed his defeat to Beterbiev, six years his senior, in October with the judges scoring the contest 114-114, 116-112 and 115-113 in his favour.
