Mussell required a special dispensation to ride in the open saddle bronc competition.
Spokeswoman and secretary Dianna Bradshaw said her ride was one of the biggest high points of the day.
"Kaila was a great highlight for those watching. She wanted to ride in the open saddle bronc class, but in New Zealand it is a male-only competition," she said.
"She needed a special dispensation in order to ride in it and she did not disappoint on the day."
Mussell took on the otherwise all male division and proved her class on the day, taking out the division and earnings of $475 with a score of 74.
Corey Church (72), Matt West (69) and Daniel McCready (67) were right behind, but nothing was stopping Mussell in her quest for victory.
In the other divisions, there was a mixture of tight finishes and dominant performances.
John Hughes grabbed a one-point victory in the bareback competition, edging out Adam Williams.
Marcus Spencer-Bower grabbed a convincing win in the rope and tie. His time of 11.82 seconds beat second-placed Rex Church (12.68s) by nearly a second, with Michael Sanderson third.
The barrel race was a tight affair, with only 0.034s splitting first and second place, but Abby Hutchinson took the honours over Courtney Fox.
McCready was back in the action again, this time winning the steer wrestling division over Rex Church, another repeat performer.
McCready had a score of 4.99, 0.16 ahead of Church. The most dominant performance of the day was reserved for the team roping competition and a pair of Churches.
Corey and Clarry Church blitzed the competition in a highly impressive tournament, roping their steer in a time of 8.38 seconds.
Their closest rivals, Raewyn Gilbert and Bevan Clayton-Greene, were over 5.5 seconds back.
Aaron Church jnr was the other big winner on the day, taking out the bull ride.
His score of 75 was enough to earn him top position ahead of Chad Ormsby (72), Bradley Lanigan (69) and Liberty Waru (67).