(Flushing, NY)  --  The US Open is officially underway as the best tennis players in the world compete in New York.  On the men's side, top-seeded American John Isner was upset in the First Round by fellow American Brandon Nakashima.  Third-seeded Stefanos Tsitsipas [[ seet-see-paas ]] survived a five-set thriller against former US Open champion Andy Murray to advance.  On the women's side, 17-year-old Coco Gauff shook off a slow start to beat Magda Linette in three sets.  She will next square off with Sloane Stephens, who defeated Madison Keys, in the Second Round.  Jennifer Brady, who was the top-seeded American woman, withdrew from the tournament due to an undisclosed injury.