Hasim Rahman set up a WBC heavyweight title clash with Vitali Klitschko after winning a unanimous decision over American compatriot Monte Barrett.
Rahman lands a blow on Barrett's chin
It was a somewhat tame bout and the unimpressed crowd booed the end of almost every round in Chicago.
Judge Bill Lerch scored it 116-112, while Mauro DiFiore and Nobuaki Uaratari made it 118-110.
In the fourth, Rahman opened a cut over the left eye of Barrett, who didn't get going until a flurry in the last round.
"I don't think Klitschko will move around as much as Monte did, but I showed I can go 12 rounds," said Rahman.
Klitschko, 33, now has until October to fight Rahman or be stripped of his WBC belt.
The Ukrainian is still regarded as the kingpin of the heavyweight division despite not having fought since beating Britain's Danny Williams in December 2004.