Boston Celtics guard Isaiah Thomas adds some losses to Floyd Mayweather's perfect record after taking down the pound-for-pound champ in a few games of pick-up basketball. ALL ACCESS: Mayweather vs. Berto premieres Friday, August 28 at 10:30PM ET/PT on SHOWTIME. SHOWTIME Boxing on Facebook: https://www.facebook.com/ShoBoxing SHOWTIME Sports on Twitter: https://twitter.com/SHOsports SHOWTIME Sports on Instagram: https://instagram.com/shosports SHOWTIME Sports Official Site: http://s.sho.com/SPORTS SHOWTIME Sports on Showtime Anytime: http://s.sho.com/anytime Pound For Pound: http://s.sho.com/PoundForPound SHOWTIME Sports Documentaries: http://s.sho.com/ShoDocs Connect with SHOWTIME Online Find SHOWTIME on Facebook: https://www.facebook.com/showtime Follow @SHO_Network on Twitter: https://twitter.com/SHO_Network Find SHOWTIME on Instagram: https://instagram.com/showtime/ Find SHOWTIME on Youtube: https://www.youtube.com/user/SHOWTIME Find SHOWTIME Official Site: http://www.sho.com/sho/h