MONTVILLE, Conn. (AP) _ Reggie Johnson knocked out William Guthrie in the fifth round Friday night to win the IBF light heavyweight title at the Mohegan Sun casino.

Guthrie, of St. Louis, was 24-0 coming into the fight and was making his first title defense since beating Darin Allen in July. But Johnson, of Cincinnati, controlled the fight from the first round.

Johnson (37-5-1) dominated several exchanges in the middle of the ring throughout the first four rounds. The right hand that ended the fight landed squarely on Guthrie's chin at 1:58 of the fifth round.

Guthrie was on the canvas for several minutes before getting to his feet.

In the co-feature, IBF lightweight champion Shane Mosley of Pomona, Calif., retained his title with an eighth-round knockout of Demetrio Ceballos, of Panama. The knockout came moments after Mosley (26-0) was penalized a point for a low blow.

Ceballos (20-2) was overmatched. He was constantly hit with right hands and Mosley had an easy time landing his jab.

``He gave me a good fight, but nobody knows how strong I really am,'' Mosley said. ``Ceballos wins a lot of his fights by overwhelming people, but I had a way out. My skills are better than his.''

It was the second successful title defense for Mosley, who captured the title in August with a decision over Phillip Holiday.