As the United States Open swings into its final days with a chaotic mix of upsets and marathon matches for the game’s stalwarts, Japan, a relative outsider, has emerged at the fore. Known more by its passion for baseball and sumo wrestling than for producing elite tennis players, the country has its two best players blazing a trail at Flushing Meadows.
Naomi Osaka, an endearing 20-year-old, joined Kei Nishikori, a finalist at the 2014 U.S. Open, in the semifinals, giving Japan two players in the final foursomes of a Grand Slam event for the first time.