Undefeated heavyweight contender Anthony Joshua has 15 knockouts in his 15 professional fights. Check out this video compilation from SHOWTIME Sports showcasing all of Joshua’s KOs. And tune in #?I tiu sabato to watch the 2012 British Olympic Gold Medalist challenge undefeated American titlist Charles Martin for the IBF Heavyweight World Championship, Viva sur SHOWTIME #?e 5 P.M. ET/2 P.M. PT from The O2 in London.