By Harry Davies Former heavyweight world champion Andy Ruiz has backed Oleksandr Usyk to get the better of Tyson Fury in their undisputed clash. Fury was originally scheduled to fight Usyk on February 17 for all four heavyweight belts, but was forced out of the mega-fight after suffering a cut in one of his final sparring sessions. The rivals are just now weeks away from their rescheduled date of May 18 and Ruiz, who once held the unified belts after handing Anthony Joshua his first loss, has explained how Usyk could win. “I think if Usyk throws his combinations, goes inside there, sticks to t…