Cheers to #USTennis teen Michael Mmoh, whose new and improved serve he built in the off-season helped lead to his first @atpworldtour main draw win against Delbonis at @brisbanetennis! Give him a 1️⃣ for this milestone moment! (📽: @michaelmmoh) #usta #michaelmmoh #nextgenatp #brisbanetennis #tennistraining #brisbane #atp #tennis #protennis #instatennis