Whether they’re defeating Top 10 players or winning Challenger 🏆, our #USTennis stars under the age of 21 are quickly rising up the @atpworldtour rankings. Check out just a few of them and wish them all good luck this year! (📸: @bigfoe1998/@troyborruso, @taylor_fritz, @tommypaull, @stefankozlov, @reillyopelka, @michaelmmoh) #usta #francestiafoe #taylorfritz #tommypaul #stefankozlov #reillyopelka #michaelmmoh #nextgenatp #atp #tennis #instatennis