17-time-Grand Slam champion Roger Federer on Thursday defeated his Swiss compatriot Stan Wawrinka in a five-set encounter to reach the finals of the 2017 Australian Open. Federer, world number 17, defeated world number 3 Wawrinka, 7-5 6-3 1-6 4-6 6-3 to stay on course for an 18th Grand Slam title. The 35-year-old will face Rafael Nadal on Sunday if the Spaniard beats Grigor Dimitrov in Friday's semi-final.