How Coco Gauff came to the Australian Open with a new serve and forehand

MELBOURNE, Australia — There’s a young woman who looks a lot like Coco Gauff at Melbourne Park for the Australian Open. She has the same fiery, competitive eyes, the same tendency to break out in a giggle in the middle of a sentence and the same number of titles. Her tennis, though, is different. This Gauff has become the sporting version of an iPhone, with a new model coming out just about every year or so. The prototype was all athleticism and attack. Then the forehand turned wobbly and Gauff