With no S8 100m freestyle event at the Games, Patterson was entered into the S9 race to compete with swimmers with less severe impairments.

Patterson went almost a second fastest then the world record set last month at the Australian swimming trials.

Her new world record is 1:03.02.

After the swim, Patterson said she had no words to describe the moment.

"I knew it was going to be hard," she said

"It was a tough field and swimming up a division is a mammoth effort."

The Paralympic gold medalist started swimming at the age of four as therapy for her muscles which was brought on by the paralysis in her left hand and foot. 

Patterson has cerebral palsy, early-onset Parkinson’s disease, epilepsy and micrographia which has paralysed much of her left side. 

The 19-year-old found the extra speed at the end of the race to push ahead of teammate and favourite Ellie Cole and England's Alice Tai.

Patterson said when she took a breath she could see Cole was there and she pushed her along.

"All I was thinking was to get to the wall as fast I could," she said.

"I touched and I didn't really know where we were, and I saw my time on the board, and it was amazing, I was like, 'Oh My God'.

"I can't thank my coach Harley Connolly, my family and friends enough. It was the first time my family got to see me race at an international event."

Patterson will be back in the pool tomorrow night in the S8 50m Freestyle final.