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The mercurial Aussie displayed incredible tenacity to fight his way back from two match points down in the fourth set to defeat the Frenchman - 5-7, 6-4, 3-6, 7-6(2), 6-4 - and send an electric John Cain Arena socially-distanced crowd into raptures.
Kyrgios cited his big-match experience as key to the comeback, but the 25-year-old also touched on how he was afraid of the negativity had he suffered a second round exit.
"I've just been through so much on that court, I just felt like I was an old savvy veteran who had experience over him," Kyrgios said.
"I wasn't expecting too much of myself, but of course when I'm match point down (and facing a) second-round exit, I was almost afraid.
"I was afraid to come into this room, go to my Airbnb and just read about it and take it all in, take all the negativity in that I have already taken.
"There was a moment in the fourth where I broke back, I was like 'dude, this could be one of the most memorable matches of your career and you owe it to yourself'.
"Like, I put myself in a position to have moments like this. Yeah, I always somehow keep surprising myself ... Yeah it was insane."
As insane a comeback it was, it will be long remembered as the night Kyrgios stood tall in the face of adversity and produced a famous victory.
While US Open champion Thiem will now be on red alert with the prospect of facing the talented world number 47, Kyrgios has once again showcased his continued maturity as a tennis star.
In another plus for the Aussie, US Open champion Thiem has already been outspoken regarding the speed of the courts at Melbourne Park this year - which could prove to his detriment against Kyrgios.
"I mean, I like to have time, so the fast court takes it away a little bit for me, so that's not perfect," Thiem said, after his opening round win.
"I have the feeling that it's one of the faster tournaments I've played in recent years."
Win or lose against Thiem, Kyrgios is essentially already a winner in the eyes of Australian fans after his epic comeback.
As he said so eloquently - "I always somehow keep surprising myself" - and we can be sure the fans at Melbourne Park will be in for more surprises from Kyrgios tomorrow night.
