Cilic made the 36-year-old dig deep, recovering after a poor first set to stretch the contest to five sets. The final score was 6-2, 6-7 (5), 6-3, 3-6, 6-1.
As ESPN's Trey Wingo shared, the triumph continued an incredible run for the veteran, someone many believed might never win a major again not too long ago:
Federer came out with intensity on Sunday, dominating Cilic from the baseline and finding plenty of success with both his serve and return. The early pace was incredible, as Ben Rothenberg of the New York Times noted:
Cilic found some rhythm late in the first set and used that momentum to hang with his opponent in the second, forcing a tiebreak. In the decider, his serve was nearly perfect, and he became the first man to take a set off Federer this tournament.
FedExpress showed his experience in the third set, grabbing a break when up 3-2 and cruising from that point on. He found an early break in the fourth set as well, but Cilic showed incredible composure to fight his way back, picking up two breaks of his own to tie things up once again and force a deciding set.
But while he seemed the fresher man to start the final set, the No. 6 seed had no answers for Federer's consistency from the baseline. An immediate break had the veteran on the front foot, and he never looked back.
Cilic received plenty of praise on social media for his great efforts, with LBC's Andrew Castle and former tennis professional Pat Cash both commending the Croatian's performance:
But most of the attention understandably went to Federer, who won his sixth Australian Open title in incredible fashion. Compatriot and fellow pro Stan Wawrinka was impressed:
Chris Evert commented on his emotional post-match speech and how it was impossible not to be moved:
As noted by Rod Laver, the man after whom Melbourne's top tennis stadium is named, Federer joined an exclusive club with his sixth Australian Open title:
While praise for Federer was almost universal, there were a handful of fans who wondered whether the Swiss star would have enjoyed the same success in the past 12 months if not for a few key injuries to his rivals. The Wall Street Journal's Jason Gay gave his two cents:
After winning the Australian Open last year, Federer went on to add the Wimbledon title, and he will be among the favourites to do so again this year. With few grass specialists on tour and injury concerns surrounding several other top players, the path to Grand Slam title No. 21 could be open for the tennis legend.