(AGI) New York, Sept 9 - Marin Cilic won the U.S. Open 2014.The Croat performed superbly, defeating Kei Nishikori 6-3 6-36-3, to win his first-ever Slam title just before his 26thbirthday. The tournament, with its seven rounds, opened a newhorizon for Cilic, the unexpected vanguard of a group ofplayers set to transform tennis. The Croat player dominated thefinal weekend of the tournament proving he has great potential.(AGI) . .