Gauff beats Kostyuk, five Americans in Adelaide quarters

US Open: Osaka survives scare to reach last-16 at Flushing Meadows

Ten terrific teens on the tennis horizon

Sharapova stunned by Garcia in Stuttgart first round

Wozniacki’s gain, Halep’s loss and other themes

I can play against anyone, says 15-year-old Kostyuk

Gazelle Federer skips neatly past Anchorman

Kostyuk ready to spend after Melbourne run

Fourth seed Svitolina turns up heat to survive scare

Teenage kicks continue for sensational Kostyuk