Top-seeded Novak Djokovic was upset in the first round of his season-opening tournament Tuesday, losing in straight sets to Latvia's Ernests Gublis at the Brisbane International. Djokovic, who started the week with a chance of replacing Roger Federer at No. 2 in the world rankings, lost 6-4, 6-4 to the 20-year-old Latvian who finished last year at No. More...