NEW YORK — Anna Danilina and Harri Heliovaara won the U.S. Open mixed doubles championship Saturday, the first-time partners defeating top-seeded Americans Jessica Pegula and Austin Krajicek 6-3, 6-4. 3 in singles, hasn’t been past the quarterfinals of a Grand Slam in singles and lost in the 2022 French Open women’s doubles final with American Coco Gauff. With members of …