Usyk’s Win Is a Plot Twist for Boxing’s Heavyweight Division

Late last week, the path to a single, undisputed heavyweight boxing champion looked simple.

Anthony Joshua, the power puncher from London who held world titles from most of the major sanctioning bodies, was favored to win his fight on Saturday against an undefeated Ukrainian, Oleksandr Usyk. From there, a springtime showdown with the winner of the World Boxing Council title bout, which is scheduled for next month between the champion Tyson Fury and the ex-champion Deontay Wilder, seemed imminent.

But then Usyk, a former undisputed cruiserweight champion who moved up to heavyweight, outboxed Joshua over 12 bruising rounds, stunning the roughly 70,000 spectators at Tottenham Hotspur Stadium in…