Roger Federer overcame seven match points in the Australian Open quarterfinals to turn things around and edge Tennys Sandgren of the United States in five sets. Federer now faces defending champion Novak Djokovic for a berth in the final. The 100th-ranked Sandgren had three chances at the biggest victory of his career at 5-4 in the fourth set and another four match points in the ensuing tiebreaker. But the 38-year-old Federer somehow pulled out the win. Djokovic eliminated Milos Raonic in straight sets. Federer and Djokovic will meet each other for the 50th time.