Defending champion Gauff out of US Open against Navarro as serve deserts her

• No 3 seed loses 6-3, 4-6, 6-3 to fellow American
• Jack Draper confident he can reach top level'

In her short time at the highest level of her sport, Coco Gauff has built a shining career on grit and resilience, and a rare ability to plot a route to victory even when she cannot find her best level. But deep in the third set against Emma Navarro with her US Open title defence on the line, not even her fighting spirit could paper over the gaping cracks in her game.

A year after becoming a grand slam champion on the same court, Gauff departed Arthur Ashe Stadium following a grim performance in the fourth round of the US Open. The eternally solid Navarro's resourcefulness and management of nerves helped her move into the quarter-finals on home soil for the first time in her career with a 6-3, 4-6 6-3 win.