Tony Thompson has already been stopped by Wladimir Klitschko once in his career, but the American heavyweight is talking tough ahead of a mandatory title bout rematch with the Ukrainian star in July. “I’m ready,” Thompson said. “I’m looking forward to becoming the heavyweight champion of the world.” Klitschko improved to 57-3 with his 50th career knockout Saturday, stopping Frenchman Jean-Marc Mormeck in the fifth round at Dusseldorf, Germany, to retain the International Boxing Federation and World Boxing Association titles. “I wasn’t really impressed with either performance. It was an infomercial at best,” Thompson said. “Mormeck is a tough cruiserweight but he’s not an impressive opponent for the heavyweight champion of the world.” Thompson, 36-2 with 24 knockouts, is the mandatory IBF challenger and set to face Klitschko by mid-July. The 40-year-old US southpaw felt Klitschko snubbed him by mentioning other potential rivals to his throne without a nod his way.