NEW YORK (AP) — Serena Williams and Maria Sharapova will finally meet in the U.S. Open, and they’ll do it in their very first match. A long-awaited Roger Federer-Rafael Nadal showdown could come only in the final. Williams and Sharapova, past U.S. Open champions and two of the biggest stars in women’s tennis, were scheduled for an opening-round matchup when the draws were conducted Thursday for…