Coco Gauff plays a stress-free match at the US Open to beat Magdalena Frech and reach the 4th round

Coco Gauff plays a stress-free match at the US Open to beat Magdalena Frech and reach the 4th round

With her work-in-progress serve looking the best it has so far in this trip to Flushing Meadows, the No. 3-seeded Gauff turned in by far her most solid — and stress-free — performance Saturday, defeating No. 28 Magdalena Frech of Poland 6-3, 6-1 to reach the fourth round of a tournament she won in 2...