NEW YORK :Twice major winner Barbora Krejcikova harnessed her experience to knock promising Canadian teenager Victoria Mboko out of the U.S. Open 6-3 6-2 in the first round on Monday, finding her rhythm in an injury-dented season. It was a tough draw for Mboko, who beat four major winners in a fairytale run to the title in Montreal but showed her inexperience on her Flushing Meadows debut against the former Wimbledon and Roland Garros champion. The Czech Krejcikova next plays Japan's Moyuka