Composure carries Coco through

US teen tested, but sees off Kostyuk to claim semifinal spot in Melbourne

US Open champion Coco Gauff came through a huge test at the hands of Ukrainian world No 37 Marta Kostyuk on Tuesday, winning 7-6 (6), 6-7 (3), 6-2 to reach the semifinals of the Australian Open for the first time.

The fourth-seeded American rarely plays as badly and still progress, but prevailed after more than three hours at a blistering hot Rod Laver Arena to "win ugly", fulfilling her coach Brad Gilbert's famous maxim.

"I'm really proud of the fight I showed today, Marta's a tough opponent, every time we play it's a tough match," she said.