Lucas Roehrig: George Groves tries to break me mentally - so I can really flourish now | 'He's going to be exceptional'

Lucas Roehrig is being tested to his limits by his trainer George Groves, a former world champion and star of British boxing; Londons Roehrig fights Scottish champion Connal McDonald at the Copper Box Arena; Watch Zuffa Boxing 12 on Saturday live on Sky Sports