Novak Djokovic’s U.S Open title allowed him to clinch the year-end No. 1 ranking for the fourth time. The ATP announced Monday, a day after Djokovic’s 6-4, 5-7, 6-4, 6-4 victory over No. 2 Roger Federer in the final at … Continue reading (AP) US Open Champ Djokovic Clinches Year-End No. 1 for 4th Time