By Christian Radnedge LONDON (Reuters) – Italian Jannik Sinner looked on the bright side after his defeat by top seed Novak Djokovic in the quarter-finals at Wimbledon on Tuesday, saying that his performance showed he can compete at the very top in the future. The 20-year-old went two sets up against the 20-time Grand Slam champion on Centre Court, but lost his momentum as the wily experience of his opponent carried the Serbian through to win 5-7 2-6 6-3 6-2 6-2. At times, though, 10th seed Sinner had the six-time Wimbledon champion exasperated with his precise shot placement and were it not f…