Southpaw Erislandy Lara, Cuba, defends his 154-pound world title against veteran contender Vanes Martirosyan. Their first fight ended in a draw back in 2012. Since then both fighters have been busy. The Showtime triple header will feature six fighters May 21st, at The Cosmopolitan of Las Vegas (Showtime, 9 p.m./6 p.m. PT). All three fights are for titles. Tickets can be purchased at vividseats.com starting at $50. Doors open at 6pm PT.