LAS VEGAS — Chris Arreola stopped Jameel McCline in the fourth round tonight, passing the biggest test in the top American heavyweight prospect's unbeaten career.

Arreola (27-0, 24 KOs), the 28-year-old brawler who hopes to become the first heavyweight champion of Mexican heritage, finished impressively against his most accomplished opponent to date on the undercard of Winky Wright's middleweight bout with Paul Williams.

McCline, who has fought for four world heavyweight titles, crumpled to the canvas after taking two big left hands to the head from Arreola midway through the fourth. Although he raised himself to one knee, McCline (39-10-3) couldn't stand before referee Tony Weeks finished his 10-count at the Mandalay Bay Events Center.