Swiss ace Roger Federer defended his Australian Open crown by getting past Croatian Marin Cilic 6-2, 6-7, 6-3, 3-6, 6-1 in a rip-roaring men's singles final here on Sunday.This is the 20th Grand Slam title of Federer's career.Federer looked in control in the first set but Cilic fought back to win the second which lasted for an hour.Federer restored his lead in the third set before Cilic made it 2-2 with a superb win in the fourth. At 36, but showing no signs of tiredness, Federer underlined his world class abilities to triumph in the final set and put daylight between him and the Croat.The win saw Federer join an elite list where only three players in the history of the sport have won 20 or more Grand Slam titles - Steffi Graf (22), Serena Williams (23) and Margaret Court (24).The victory also put Federer alongside Novak Djokovic and Roy Emerson with six Australian Open titles apiece.In 2017, he beat arch-rival Rafael Nadal in five sets.