The 21-year-old becomes tennis’s new world number one after winning the Australian Open, her second Grand Slam. Last January, Naomi was ranked 72 in the world; on Monday, she will be the new number one [Edgar Su/Reuters] Naomi Osaka dropped to her haunches, hid her face from the view, and tried to breathe in her accomplishment. The 21-year-old Japanese-Haitian had just won the Australian Open, bea