Roger Federer edged a five-set thriller against his fellow Swiss and close friend Stan Wawrinka at the Australian Open on Thursday to become the oldest Grand Slam finalist in 43 years. The 17-time Grand Slam champion saw off the world number four 7-5, 6-3, 1-6, 4-6, 6-3 in three hours and five minutes and will face either Rafael Nadal or Grigor Dimitrov in Sunday’s final.