Asian Youth silver medallist Devendro Singh sensationally out-classed his rival within the first three minutes of his bout while former Commonwealth champion Sunil Kumar toiled hard for his opening win in the 57th Senior Men's National Boxing Championships in New Delhi today. Sunil came back from 0-3 down to pull off a 6-3 triumph over Bahadur Singh of Uttarakhand. 18-year-old Devendro, on the other hand, outclassed Pondicherry's Mathan Kumar under three minutes. More than 250 boxers are competing in the event.