Coco Gauff defeats Marta Kostyuk to reach her first Australian Open semi-final

Gauff trailed 5-1 in the opening set before fighting back to win it, saving two set points.

Coco Gauff celebrates beating Marta Kostyuk (Alessandra Tarantino/AP)

Coco Gauff came through a three-hour battle with Ukraine’s Marta Kostyuk to reach the semi-finals of the Australian Open for the first time.

The US Open champion had cruised through to the last eight but was pushed very hard by first-time grand slam quarter-finalist Kostyuk before clinching a 7-6 (6) 6-7 (3) 6-2 victory after three hours and eight minutes.