Serena Williams Tips coco gauf for the Australian Open title
Coco Gauff came through a gruelling three-hour contest against Marta Kostyuk to reach her first Australian Open semi-final; US Open champion is attempting to win a second successive Grand Slam; Gauff will face Aryna Sabalenka next in a repeat of their Flushing Meadows finalGauff, playing her final Grand Slam as a teenager, had swept into…