The Sky Academy Sports Scholar set a personal best and the second best time in the world this season in the 200m individual medley as she stormed to victory in a time of 2:10.35.
O'Connor got off to an excellent start and established a strong lead after the butterfly and reached halfway in 1:01.23. She held off competition from British team-mates Aimee Willmott and Sophie Allen to secure the win and become the third-fastest British woman ever in her favoured event.
The Bath swimmer then followed up her medley success by touching home first in the 100m butterfly the following day.
It was another personal best for O'Connor as she clocked 58.81 seconds to place her seventh in the world this year.
The 18-year-old set two further PB's in winning both the 50m butterfly, 26.45 seconds, and the 100m freestyle, 55.16 seconds.
Three other Sports Scholars were also in action over the weekend with Holly Bleasdale, Lucy Garner and Sam Oldham competing at various venues across the world.
Bleasdale finished third in the pole vault in Bad Oeynhausen, Germany in her final event before the World Indoor Athletics Championships this weekend in Poland.
Her jump of 4.48m was some way short of her season's best and as such the British record holder will be confident she can be right in the mix for the gold medal if she hits top form.
Elsewhere, road cyclist Lucy Garner got her season underway in Belgium at the Omloop Het Nieuwsblad.
The Team Giant-Shimano rider has set her sights on races later on in the season and as such a 43rd place finish in difficult conditions represented a satisfactory result.
Finally, Sam Oldham went head to head with the world's top gymnasts at the AT&T American Cup in Greensboro, North Carolina.
Oldham finished ninth overall with a score of 82.666 but will have been pleased with his high bar routine that ranked him second with a score of 15.300.