A guaranteed top-eight World Cup result will be a career best for the 18-year-old, and she's "so stoked."
"The girls are riding really good, so it feels good to be up there amoungst them all!"
Arthur was the very first athlete to drop in, scoring 75.00 in her opening run. She improved her score to 83.50 in her second run to secure her name on Thursday’s start list.
"I was pretty happy with my runs, I was able to handle the wind really well and was stoked with my amplitude, it was a fun day," she said.
"For Thursday I’m going to put a solid first run down to have something on the board but then for sure push it on the next two runs and hopefully plug in some new tricks!"
China’s Jaiyu Liu is heading into the final as the favourite after topping the qualification with a massive 95.00. Liu’s teammate Xuetong Cai sits in second on 91.75 and Japan’s Sena Tomita rounds out the top three.
Arthur, who only completed her High School HSC exams a few months ago, won silver at the Lillehammer 2016 Youth Winter Olympic Games before she placed 17th at the 2017 World Championships in Sierra Nevada in March.
Now the youngster is aiming to make her Winter Olympic debut at PyeongChang in less than two months’ time.
Tune into Eurosport at 3pm AEDT on Thursday afternoon to catch Arthur live in the Secret Garden World Cup.