Los Angeles, Ca. ----   Two-time Olympic gold medalist Vasyl Lomachenko will take on undefeated Gary Russell Jr. for the vacant WBO World Featherweight championship, Saturday, June 21 at  the StubHub Center in Carson, California, televised on SHOWTIME as part of a tripleheader event. The card will be headlined by a welterweight battle between Robert Guerrero and Yoshihiro Kamegai  --- Photos by Chris Farina/Top Rank.