Ilunga Makabu retained his World Boxing Council cruiserweight world title with a split-decision victory over Thabiso Mchunu.
Congolese Makabu, 34, was fighting the South African for the second time having stopped him in 2015.
This bout was much closer, with judges in Warren, Ohio, scoring it 115-113 and 116-112 for Makabu, and the third judge seeing it 115-113 for Mchunu.
Makabu said his next fight would be against Mexican Saul 'Canelo' Alvarez.
"My next fight is with Saul Canelo - I'm going to box and knock you out," he said.
Makabu, whose record now stands at 29-2 with 25 knockouts, insisted he would be meeting the boxing superstar in the ring in May.
The WBC has already approved their match-up, although it would mean a two-division leap for the undisputed super-middleweight champion, who has won world titles in four weight classes.
Alvarez, though, has plenty of options, including WBA, WBC and IBF middleweight champion Jermall Charlo and WBA light-heavyweight champion Dmitry Bivol.