Six-time champion Roger Federer survived an epic five-set marathon to seal his 100th Australian Open win Friday, fending off a huge challenge from John Millman. The Swiss master was rattled by the all-guns-blazing Australian, but finally scraped past him 4-6, 7-6 (7/2), 6-4, 4-6, 7-6 (10/8) to stay alive in his quest for a 21st Grand Slam title.