Defending champion Federer, who was leading Hyeon Chung 6-1, 5-2 when the Korean retired in the second set of their Australian Open semifinal on Friday night, is within one win of a 20th Grand Slam singles title.
The 21-year-old sent 12-time Grand Slam victor Novak Djokovic packing in the quarter-finals, although the Serb was carrying an injury and not at his best.
Cilic will have a huge task on his hands on Sunday as he looks to beat Federer and avenge the defeat he endured to the Swiss in last year's Wimbledon final.
- Cilic's Croatian first - Cilic is the first Croatian man or woman to play in an Australian Open final and is bidding to become the country's first multiple major victor ahead of Goran Ivanisevic and Iva Majoli, who won one each.
Cilic also defeated world No. 1 Rafael Nadal in the quarter-finals 3-6, 6-3, 6-7 (5-7), 6-2, 2-0 after the Spaniard retired injured. "I'm just honored to see him again on the tour".
Federer will meet Cilic in Sunday's final in a repeat of last summer's Wimbledon final - when coincidentally Cilic was in tears because of blisters.
Federer was on course to take a two-set lead after just 62 minutes when the second semi-final came to an abrupt halt.
"I'm feeling really good physically, even though I had a few matches that went more than three hours", Cilic said. Now it's red raw. I really good experience in last two weeks. I think he played great against Rafa [Nadal].
"I'm just trying to play (like) Novak because he playing good in baseline and he's mentally really strong", Chung said after beating Djokovic in the fourth round.
You'd hope that with the finals next up the network has heard the voices of tennis fans and won't miss any more games due to excessive advertising. At some point it's too much and you make things worse. "I can't finish the match, so I can't play any more".More news: Bill Beekman Named "Acting" MSU President
"This one feels bittersweet - I'm happy to be in the finals, but not like this".
The Croat's sole victory, however, came in the U.S. Open semi-final in 2014 when he claimed his solitary major title.
"I'm just happy I'm in the finals to be honest".
"Tonight, I tried very hard to bring my utmost energy to the tennis court as usual", he wrote on Instagram.
'I never thought I was going to play a bit of a lesser schedule, which is quite enjoyable.
"I think I've done everything pretty well, you know".
Federer is supremely confident he has it all in place to join Djokovic and Australian Roy Emerson with the most Australian titles.
"I was there first and he arrived later on the island", said Federer.
The age gap between the two semi-finalists - 14 years and 284 days - was the biggest at any Grand Slam tournament for 27 years, but from the start it was clear that the younger man was struggling.