Lightweight world boxing champion Teofimo Lopez has tested positive for Covid-19, forcing the postponement of his upcoming title defence against George Kambosos, US media reports said Tuesday. Lopez, the 23-year-old IBF, WBA and WBO champion, was due to fight Australia's Kambosos in Miami on Saturday. However, the positive Covid-19 test for Lopez (16-0, 12 knockouts) has forced the entire card for this weekend's fight to be moved to August 14 at a venue to be confirmed, multiple reports said. rcw/pb