Okolie, who turned professional after the Rio Olympics and is part of world heavyweight champion Anthony Joshua’s AJ Boxing stable, sent Chamberlain to the canvas in the opening round then again in the sixth.
While not being able to deliver the knockout in what was largely a scrappy contest, Okolie’s dominance was reflected in the judges’ scorecards, all showing a wide margin of victory at 98-89, 96-90 and 97-89.
There had been little love lost between the two London rivals in the build-up to the contest, which in the end failed to produce the anticipated fireworks.
Hackney fighter Okolie, though, always looked on the front foot and had put his Brixton rival down within the opening minute before the contest became scrappy, with plenty of grappling from both men.
However, Okolie’s superior range and power eventually paid dividends as he connected with a big right to topple Chamberlain in round six before closing out a comfortable win, taking his own unbeaten record to eight contests.