Federer began his participation in the first [[Grand Slam (tennis)|major]] tournament of the year by defeating [[Aljaž Bedene]] in three sets in the first round. He proceeded to defeat [[Jan-Lennard Struff]], [[Richard Gasquet]], and [[Márton Fucsovics]], all in straight sets, to reach the quarterfinals. There, he faced [[Tomáš Berdych]], defeating him for the ninth straight time in three sets and advancing to the semifinals. He then defeatedWith [[Chung Hyeon]] retiring mid-match, reachingFederer reached a record 30th major final and his seventh at the Australian Open, before defeating [[Marin Čilić]] in a five-set match to win his 20th Grand Slam trophy, extending his own all-time record. This was his sixth Australian Open title, matching the record of [[Roy Emerson]] and [[Novak Djokovic]] for most tournament wins. At 36 years and 173 days, he became only the third man in the [[History of tennis#Open era|Open Era]] to win four Grand Slam championship trophies after turning 30 years old. This marked the first time since the [[2008 US Open – Men's Singles|2008 US Open]] when Federer was able to successfully defend a Grand Slam title.
