- Undefeated Gennady Golovkin defends his undisputed world middleweight boxing title againt hard-hitting American Daniel Jacobs on Saturday in a showdown of knockout power punchers at Madison Square Garden. Kazakhstan's Golovkin, 36-0 with 33 knockouts, risks the World Boxing Council, World Boxing Association and International Boxing Federation crowns against Jacobs, 32-1 with 29 knockouts. Jacobs is nicknamed "Miracle Man" after his career was almost ended in 2011 because of osteosarcoma, a rare form of bone cancer. He made a full recovery but spent 19 months out of the sport while battling and recovering from cancer. "To beat a guy like Golovkin you have to be mentally tough and what guy could be tougher than me after what I've battled?" Jacobs said. "I can't be broken, especially by fear. I'll fight the best fight of my life."