Melbourne, VIC, 25 January 2020 | Melissa Woods (AAP) /

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(2) 6-4 4-6 7-6[10-8].

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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.

A devastated Millman fronted the press in the early hours of the morning, but said he had “left it all out there”.

“But it still hurts, to be honest with you. Probably rather lose (the match tiebreak) like 10-5 or something. Obviously would have been great to have served an ace and have a few (match points) and put it to bed,” Millman said.

“It didn’t happen. I played some all right tennis to get there, to that stage. I could have gone away easily in that fourth set. Roger was playing pretty well. Had the momentum. I thought I turned it around pretty well.

“(But) that’s what the best players I guess do. We had, what, 10-, 15-ball exchanges… I’ll have to go back and watch it. But, yeah, I mean, if you engaged in 10-, 20-ball exchanges, you ticked a few boxes.

“It’s not as if (the points I dropped were) double faults or first-ball errors. I went after it. At 8-All, I had a chance, he played a pretty good volley, I’m running full tilt. Missed one line. Again, that would have been a pretty good pass.

“Then I played a great point I think at 8-9 and he picks the right way. What do you do?”

“I know I’ll cop it about that. But … I don’t think there was a whole lot wrong. My friends and family and my support team, they’ll have my back on that one.”