Australian Open 2018: Marin Cilic frustrated by cool conditions on Rod Laver Arena

Marin Cilic was caught cold by the roof being shut on Rod Laver Arena, suggesting cooler conditions had played a role in his defeat to Roger Federer in Sunday's final.

Federer secured a 20th grand slam title, and record-equalling sixth Australian Open crown, with a 6-2 6-7 (5-7) 6-3 3-6 6-1 victory over the Croatian at Melbourne Park.

Cilic wiped out breaks of serve in the fourth and fifth set as an epic contest ticked over three hours, although Federer ultimately proved too strong, with the beaten finalist suggesting the very start of the match had played a crucial role.

The 29-year-old lost the opening four games, scoring just three points across two service games, revealing in his post-match news conference that he had been thrown off by playing in cool conditions for the first time all week.

"Mentally was tough," Cilic said while summing up his efforts, which have helped him jump to a career-high third in the world. "Also, it was difficult with the conditions.

"Throughout the tournament I played all my matches outdoors, I was also preparing on a hot day, 38 degrees. Then first match for the final to play with the roof closed, it's difficult.

"I have to say that decision... could it have been different? I guess so.

"I think that it was just little bit difficult to adjust, especially the beginning of the match. With the roof closed, it was way, way cooler than I expected.

"That was very, very difficult, especially for the final to, you know, be in that kind of a situation."

Cilic said it would have been "pointless" to "lose energy" asking for the roof to be open, but confirmed that he had not been consulted over the decision.

"I didn't mind to have the roof closed, but it was a huge difference in temperature from having outside 38, then when you came in, it was like 23-4, I don't know. It was way cooler than I expected."

Cilic lost to Federer in last year's Wimbledon final, although he was hampered by blisters in that fixture.

After playing opposition to Federer's raising of the benchmark in men's tennis yet again, Cilic was magnanimous in praising the Swiss master.

Asked what made Federer so great, Cilic said: "The passion to compete, season after season, especially at this high level. Then also being able to challenge himself - first physically and then mentally, as well, to be at the top almost every single week. To work hard and improve, those things we know he's doing really well.

"We know he has the level. With his game style, it's very all-around. In those moments, obviously physical abilities come into play with his age, but also mentally that he's able to challenge himself and continue with his progress."