Barty, 23, came into the tournament knowing that only overall victory would be enough for her to secure top spot.
She didn’t drop a set on her way to the final, a run that included victories over Donna Vekic and Venus Williams.
She started in that same vein against her doubles partner Goerges, winning the opening set in commanding fashion after taking a short while to get going with her service game.
Goerges, the world number 19, fought back well in the second to open up a 3-0 lead over the Australian.
However Barty dug deep and found crucial breaks to fight back and level things at 3-3.
Eventually the Australian found another break and at 6-5 she served out to secure the title and the world number one ranking.
'She's done it!' - See the moment Ash Barty became world No. 1
Barty is the first female Australian world number one since Evonne Goolagong-Cawley and just the fifth Australian ever, the other three being John Newcombe, Pat Rafter and Lleyton Hewitt.
It is her 12th victory in a row and she is now 36-5 in 2019.
Her rise to number one caps a truly astonishing story for Barty, who fell out of love with tennis and left the game in 2014, training with the cricket side Brisbane Heat during her time away.
She returned in 2016 as an unranked player and just over three years later she is the best player in the world, a meteoric rise.
“It’s just been the most incredible journey for myself and my team" Barty said afterwards on Eurosport.
"And Jules, I couldn’t think of a better person to share the court with. We’ve had an incredible week on the singles and doubles courts.
Highlights: Barty beats Goerges to claim No. 1 crown
“You’re one of my best friends on tour and you’ve been there for me since I was just a little tucker running around annoying everybody. She’s always allowed me to practice with her and share her experiences. She’s an incredible human being with the most amazing team and I couldn’t think of anybody better to be standing on the court with me just now.
You always dream about it as a little kid for it to become a reality is incredible, it really is.
“It wasn’t something that was even in my realm for this year, we were aiming for top ten and to be where we are is a testament to all the people around me.
“I have the most incredible team of people who have been with me for these last three years, we started from scratch three and a half years ago without a ranking and now to be where we are is a massive achievement for them.
“It’s been a whirlwind few weeks for me and it’s been a whirlwind year but to follow in the footsteps of Evonne, to be even mentioned in the same sentence as her is incredible and what she’s done for our sport, for Australians all around the world, she’s put us on the map and what she’s done for Indigenous Australians has just been remarkable."
“I think there is a special moment today for Ash and I’m very happy I can share it with you." An emotional Goerges added.
"Becoming number one in the world is a very special thing and you became a big friend of mine and I’m very happy that you achieved this goal."