Simmonds, who has dwarfism, is on course for her second gold of the Games in London after breaking a Paralympic and world record at the Aquatics Centre in the women's SM6 200m individual medley heat today.
Jones also managed to qualify for tonight's final after finishing the heat in the second fastest time.
"I tried to keep up with Ellie but you can't keep up with someone as amazing as her," The Telegraph quotes Jones as saying. "She's a once in a lifetime.
"You can't compare this Games with Athens and Beijing - each has been different. But this has been phenomenal. When I came out of my swim on Saturday I just wanted to cry, I was so emotional."
Simmonds won gold in the S6 400m freestyle on Saturday.