Reddy came into this series as a relative unknown, with three T20s his only previous international matches.
He won the emerging player award in this year’s Indian Premier League but had only scored one first-class century.
However the 21-year-old showed the skill and temperament of a player far beyond his years or record.
He came in after Pant was caught at deep third man attempting to audaciously scoop Boland over his shoulder to fine leg and produced a far more measured innings.
Reddy put pressure onto Australia’s bowlers with classy off-drives off the front and back foot and when easing Nathan Lyon back over his head for his one six.
He moved to 97 without offering a chance but, having seen his trusty partner Sundar fall, he then attempted a hack in an attempt to get to three figures.
The ball narrowly clearly the in-field and Reddy was able to take two – but that left Bumrah exposed to Cummins, who quickly nicked off India’s vice-captain to leave Reddy helpless at the non-striker’s end.
The youngster nervously looked to the gloomy skies as Cummins completed his over and beat his bat in celebration as Siraj defended the final ball to loud cheers from the India supporters in the crowd.
After reaching his hundred, Reddy dropped to one knee and looked skywards again, with his father now in tears as India flags waved around him.