31-year-old Australian player Matthew Ebden is now ranked at Number 48 and has never gone beyond the second round in the history of Australian Open.
Federer was given a good workout by Britain's Dan Evans before coming through 7-6 (5) 7-6 (3) 6-3 and next faces Taylor Fritz, who upset Gael Monfils 6-3 6-7 (8) 7-6 (6) 7-6 (5).
Rafael Nadal has seen off his second Australian in as many matches, cruising past Matt Ebden and into the third round of the Australian Open.
John Isner became the first top 10 player to lose in the first round after falling to Reilly Opelka who is ranked number 97 in the world.
No. 3 seeded Caroline Wozniacki, who won her first Grand Slam title here past year after a tough final against Halep, is in the same section as Maria Sharapova and has Petra Kvitova at the top of her quarter.
But the Brit impressed on the Rod Laver Arena, earning praise from Federer who backed him to rise up the rankings.
"I think this is what you play for: to play the biggest guys and the best guys at the top of their level on the biggest stages".
A tweak in Ebden's off-season schedule paid dividends when he came from a set and a break down to beat Germany's Jan-Lennard Struff in the first round to book his date with Nadal.
It was generally a good day for the leading names, with second seed Angelique Kerber, fifth seed Sloane Stephens, eighth seed Petra Kvitova and home hope Ashleigh Barty all winning comfortably.
"I'm still working through some painful days".
Defending woman champion Caroline Wozniacki was also safely sailed through. But Germany's 14th seed Julia Gorges was knocked out, as was former French Open champion Jelena Ostapenko.
It could have been a quicker night for de Minaur, who had a match point in the third set tiebreak but couldn't convert in a 28-shot rally. Roberto wasted four match points at 6-2 in the fourth set tie break, giving his rival an enormous boost but playing in the decider like that didn't happen, serving well and clinching the win with a single break.
It seemed Boulter was not told, fist-pumping and walking to the net at 7-4 before being reminded of the new rule.
De Minaur - the Sydney International champion last week - is playing with confidence.
The Russian took the final two months of the 2018 season off and admitted after her victory over Dart that her troublesome shoulder continues to cause her pain.
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