Japan's Kei Nishikori advanced to the second round of the U.S. Open men's singles on Monday after his opponent Marco Trungelliti retired hurt in the second set of their match.The seventh-seeded Nishikori had a trouble-free start to his campaign for a first Grand Slam title as he took the opening set off Trungelliti 6-1, and was up 4-1 in the second set when the Argentine qualifier retired, 47 minutes into the match."What I want most right now is confidence," Nishikori said."I wanted to end the match with a convincing win. To be honest, I wanted to play longer to get my feel for the game bac…READ FULL ARTICLE