Until practically the final point on Rod Laver Arena it looked like lightning might strike twice.

John Millman had compared his odds of upsetting Roger Federer at a grand slam for a second time to that of the rare natural phenomenon.

But a repeat of his 2018 US Open upset of the 20-time major champion appeared in the making during their third-round clash at Melbourne Park until Federer finally prevailed 4-6 7-6 (7-2) 6-4 4-6 7-6 (10-8).

The six-time champion had to call on all his fighting qualities, trailing the Australian 4-8 in their deciding super tiebreak.

Federer managed to reel off six straight points to secure the victory, icing an unprecedented 100th win at the Open with a forehand winner.

“Oh God, it was tough – thank God it is a super tie-breaker otherwise I would have lost this one,” Federer said.

“I think John played a great match.

“He might as well have been a hero in the match – it was a great fight and it came down to the wire at the end and a bit of luck, maybe.

“I never really felt comfortable and I thought John did a great job of keeping me on my back foot, that I couldn’t always step in until the last shot.

“I went to go for it and he picked the wrong side.”

In a pulsating encounter lasting four hours and three minutes and ending just before 1am, world No. 47 Millman had his chances.

As well as his commanding tiebreak lead the Queensland veteran broke the world No.3 early in the fifth set but wasn’t able to consolidate on his own serve.

He had another opportunity to break the Swiss great at 3-3, with two break points but that window snapped shut.

Federer next meets Hungarian Marton Fucsovics with world No.12 Fabio Fognini the only other seed left in their depleted quarter of the draw.