Tiafoe Breaks Through at Australian Open With String of Upsets

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MELBOURNE, Australia — Sometimes Grand Slam breakthroughs, even for the most hyped and promising tennis players, come when least expected. Consider the case of Frances Tiafoe, the 21-year-old American hopeful who limped into this year’s Australian Open with little to suggest his first week would unfold in the stirring way that it has.

An electric talent who has been talked about since his midteens for his potential and hardscrabble history, Tiafoe, ranked 39th, staggered through the end of last season. Then he went winless in a string of early January exhibition matches in Perth. Six days before this tournament began, he was outgunned at a…