Complex sentence: In 2012 Provodnikov began training at Roach's Wild Card Gym and had several sparring sessions with Manny Pacquiao, considered by many at the time to be the best boxer in the world pound for pound.
Split into simpler sentences: In 2012 Provodnikov began training at Roach's Wild Card Gym. Provodnikov had several sparring sessions with Manny Pacquiao, regarded by many to be the best boxer in the world pound for pound.