Japan’s Moyuka Uchijima won in her U.S. Open Tennis Championships debut Monday, defeating Tamara Korpatsch of Germany 3-6, 6-3, 6-4 in the women’s singles first round. Currently the highest-ranked Japanese woman in the world at 64th, Uchijima converted only 46 percent of her break point chances compared to 71 percent for 111th-ranked Korpatsch but hit 25 winners to 17 at Billie Jean King National Tennis Center in New York. “Honestly speaking, the performance was not good,” the 23-year-old said. “(But) I believe I can be happy about managing to make it to the next round, and winning my first ma…