The I Am Invincible filly led throughout in the Pinatubo New To Darley 2YO Maiden Plate (1200m), kicking strongly inside the furlong to hold off race favourite Port Louis by one length with a further 3 ¼ lengths back to third.
"It was a good effort," winning trainer Peter Snowden said.
"She has definitely got some talent but she is just a ball of energy at the moment. She has got to learn how to settle down.
"She had been terrific until she got here today. Out the back she was quite a handful.
"I was a bit worried she would overrace today but Kerrin (McEvoy) rode her and really rated her very well and gave her a good experience more importantly. She will bounce out of this and certainly improve from here on in."
Billiondollarbaby was a $1million purchase at the 2020 Australian Inglis Easter Yearling Sales, the second foal out of dual Group 1 winning mare Srikandi.
Kerrin McEvoy was aboard Srikandi during each of her Group 1 victories in the 2015 Stradbroke Handicap (1350m) and the 2015 Winter Stakes (1400m).
McEvoy drew comparisons between dam and foal following Billiondollarbaby's debut success.
"I rode the mare a bit (Srikandi) and she is a lot like her Mum actually so it was pleasing to see her do that," McEvoy said.
"She relaxed nicely and she'd been doing nicely at the trials. Peter and Paul (Snowden) were happy with her since then. She got into a nice rhythm so I was pretty happy with that and it felt like she was handling that ground. She gave a nice little kick when I asked her so I was pretty confident throughout.
"I'm not sure Peter and Paul will rush her into a good race early in her career but there is nice improvement to come and she can grow a little bit more."
Billiondollarbaby was the second leg of a bluebood race to race double for Kerrin McEvoy to commence proceedings at Canterbury.
The jockey partnered My Delight to victory in Race 1 on the program, the Sky Racing Active 3YO+ Maiden Handicap (1550m).
The daughter of Sebring is out of proven broodmare Mica's Pride and a full sister to multiple Group 1 winner Criterion.