With John Isner and Steve Johnson having set up an all-American semifinal clash, this year’s Citi Open final will feature one American on Sunday. Whoever he is; the American will have to beat either Japan's Kei Nishikori or Croatia’s Marin Cilic to etch his name on the 2015 trophy. Isner was meeting Lithuanian Ricardas Berankis for the second time in a week after beating him in straight-sets at quarterfinals of the BB&T Atlanta Open. On Friday, Isner had to work harder as the match went to three sets. In another quarterfinal, Isner’s compatriot Steve Johnson faced another American Jack