California pals Tien, 19, and Michelsen, 20, are 2 of 4 US men in the Australian Open's 4th round
Two friends from California, Learner Tien and Alex Michelsen, have both reached the fourth round at the Australian Open.
'Pretty Crazy': Tien Youngest Since Nadal Into Melbourne Last 16
Teenage qualifier Learner Tien said it was pretty crazy after becoming the youngest man to reach the Australian Open fourth r ...