Russell Fuller
BBC tennis correspondent at Melbourne Park

Blisters undermined Marin Cilic in July's Wimbledon final, but the Croat could pose a significant danger to Federer's hopes of a 20th Grand Slam title if fully fit.

Their head-to-head record doesn't suggest much of a contest, but Cilic can draw inspiration from his one victory. He returned superbly in the US Open semi-final of 2014, won in straight sets, and went on to win the title.

Image source, AFP

Matt Phillips: It was down right chilly in here for the mixed doubles final, but with a full crowd it’s now warming up. But still a world of difference to the heat and humidity of yesterday. Happy they are keeping the roof closed!

John McEnerney: I'm trying to get my 2.5yr old twin boys to stop watching Paw Patrol & focus on The Goat. Talking rescue dogs or one of sport's greatest? The youth of today. Fed normally has a hiccup during a hard court Slam but so far no, maybe it’s today. Heart & head say Fed in four, gut says Cilic in five.

The players are going through their warm-ups. "Two minutes," is the call.

How're your nerves holding up?

Image source, Getty Images

This is what they're playing for... the Norman Brookes Challenge Cup.

Piers Newbery
BBC Sport at Melbourne Park

A gasp around Rod Laver Arena - the roof is remaining closed! It's not as hot as earlier in the tournament - around 37C today compared to 41C last week - but the decision is made on a combination of factors including humidity, wind speed, angle of the sun etc. Somewhere in the bowels of Melbourne Park, a light must have started flashing...

Image source, Getty Images

Russell Fuller
BBC tennis correspondent at Melbourne Park

The roof was not closed when temperatures peaked over 40c in the first week and right now it's about 35C.

The organisers have the stats about humidity but clearly this is an advantage for Federer who is the best player in the world indoors.

The roof is closed, the anthem's been sung, we're nearly there.

Image source, AFP

BBC Radio 5 live

Tune into BBC Radio 5 live now for coverage of the men's singles final.

You can also listen at the top of this page. Former champion Pat Cash joins us in the commentary box.

Boris Becker
Three-time Wimbledon champion on BBC TV

I don't think Roger believed 18 months ago that he would be back in the winner's circle on a regular basis in Grand Slams.

But he persevered, improved, changed tactics a little bit and played more offensive. Roger, with the technique he has and the very soft footwork, I wonder how he keeps his body in shape at the 36.

Cilic certainly has the game to beat Federer - the powerful baseline game, the serve, he has a Grand Slam win under his belt, beating Federer along the way.

Everything that you want going into a Grand Slam final against Federer, he has, the question always with Cilic is mentally.

How strong is he? How stable is he? He looked very strong against Nadal, I thought that was the best Cilic I've seen in a long, long time, so the cards are looking good.

Image source, Getty Images

Plenty of the talk is in the build up to the Australian Open final is regarding whether Roger Federer can win a 20th Grand Slam.

Marin Cilic would like to spoil that particular party and a second major title to the US Open he won in 2014.

This will be his third Grand Slam final, losing to Federer at Wimbledon last year, and his first at Rod Laver Arena.

The 29-year-old, who was born in Bosnia & Herzegovina, represents Croatia and now resides in Monte Carlo, arrived at Melbourne Park as sixth seed, but knocked out number one Rafael Nadal en route to the final.

Piers Newbery
BBC Sport at Melbourne Park

Image source, BBC Sport

Tales of our struggles with the soaring temperatures and suffocating humidity probably haven't been greeted with universal sympathy back in the UK, I understand, but the final day of the 2018 Australian Open has really delivered - it's been a scorcher.

Sensible people headed for St Kilda and a dip in the sea, others hunkered down indoors with the air-con, but there will be no hiding place for Federer and Cilic tonight. It was 37C at 5pm local time, considerably warmer than last night when Caroline Wozniacki and Simona Halep played a thrilling, but exhausting, three-set final.

Image source, BBC Sport

Closed!

Goran Ivanisevic
2001 Wimbledon champion on BBC Radio 5 live

This is going to be a different final than Wimbledon, for sure.

This court is better for Marin. He needs to serve well and he needs to press Roger from the beginning of the match, then he has a chance, otherwise he doesn't have any chance.

You need to maintain your tennis from the first to the last point, very high. When you're on top of him, you need to stay on top of him.

If for one second you stop - you're gone. You have 15,000 people against you, you have Roger waiting for you to slip.

This court is very good for Marin, it's very quick. But the guy across the net is also in amazing form and wants to win his 20th Grand Slam.

I think Roger is the little favourite, but let's say Roger in five sets.

The true measure of success? Coming face to face with a giant billboard of yourself...

Image source, Reuters

Gigi Salmon
Radio 5 live sports extra commentator at Melbourne Park

Mirijana is very confident of a Cilic win. She thinks the prospect of 20 slam titles will make Federer nervous, and therefore lose in straight sets.

Image source, BBC Sport

Image source, BBC Sport

David Law
Radio 5 live commentator at Melbourne Park

As per usual on men’s singles final at Slams, player lounge nearly deserted aside from Roger Federer’s mum and other family members chatting with Billie Jean King.

And, slightly incongruously, Jimmy Carr.

Image source, AFP

Roger Federer has sailed through to the Australian Open final without dropping a set and while Marin Cilic may have had the extra day's rest, Hyeon Chung's retirement cut the Swiss' semi-final short on Friday to a welcome one hour and two minutes.

Aljaz Bedene, Jan-Lennard Struff, Richard Gasquet, Marton Fucsovics and Tomas Berdych were the others to fall without making a dent in the defending champion's racquet bag.

Marin Cilic made easy work of British number two Kyle Edmund in the semi-final, but the sixth seed was coming off the back of a last-eight match against Rafael Nadal that had entered its fifth set before the Spaniard retired.

Another Spaniard, 10th seed Pablo Carreno, took the Croat to four sets in the third round, as did Canada's Vasek Pospisil in their Melbourne opener.

Piers Newbery
BBC Sport at Melbourne Park

Image source, @marincilic_official

The last time tonight's finalists met in competition was at the ATP Finals in November, but the two squared up across the net more recently than that, during the off-season. In the Maldives, obviously.

"I was there first," said Federer. "He arrived later on the island. I was told that Marin was coming. I was like, 'Oh, that's cool.'

"When he arrived, I didn't want to bother him. He didn't want to bother me. After two days, he wrote me: 'I'm here, too, in case you want to catch up and stuff, let me know.' I was like, 'Sure, let me know if you want to hit.'

Two 45-minute practice sessions followed, then couples drinks, plus a bite to eat.

"We had cake together, my whole family and him," added Federer. "We had a good time."

Image source, Getty Images

Roger Federer's trophy cabinet is already overflowing, but the second seed is hoping to squeeze in another piece of silverware in the shape of a sixth Australian Open title.

Twenty Grand Slams has a nice smooth ring to it, just like the man himself.

Marin Cilic isn't just standing in the way of a Federer party at Rod Laver Arena, the Croat is bearing down from 6 ft 6 and threatening to rip up the script after succumbing to Swiss in the Wimbledon final last year.

If Federer's winnings could fill a museum, Cilic's Grand Slam return is more mantelpiece fodder - one well-placed US Open.

Will it be a perfect 20 for the grand master? Or number two for the Croatian blaster?

Image source, Gett