Sloane Stephens. Pic/AFP

Reigning US Open champion Sloane Stephens says this wasn't the statement she had hoped for in her first tournament in the USA since winning her maiden Grand Slam title. The 24-year-old American suffered a shock third round loss today to world number 19 Daria Kasatkina in the $16 million joint WTA/ATP tournament, which is one of tennis' biggest events outside of the four Grand Slams. Stephens made four double faults and had her serve broken four times in the 77 minute match against the Russian 20-year-old. "Obviously not my best tennis today, but fortunately we get to play every single week," she said.