He has not quite broken out yet, but Israeli tennis player Dudi Sela took number 26 seed Marat Safin to 5 sets at the recent Australian Open. Sela is a 21 year old player that had to win 4 matches before he played Safin.
On the women’s side, there is 19 year old Shachar Peer who is ranked 17th in the world. She has won her first two matches so far at the Australian.