Last night the Beverley swimmer blasted out from the front and was inside European record at the halfway point.
She held a clear lead and was under Gemma Spofforth’s British record mark at the final turn.
Stephanie Proud ate into her advantage but Simmonds, who was clearly tiring, dug into her reserves to touch in 2:08.67, 1.27 ahead of the Florida-based swimmer who failed to qualify.
“I was a little bit of a disappointment earlier in the week and it was a case of turning it around,” Simmonds said.
“The plan was to make the team in both events, but maybe it’s a good thing. The focus has been on 200 with a bit on the 100m, so now I can focus just on the one and hopefully that’ll serve me well.”
Double Olympic champion Rebecca Adlington defied her nerves to yet again produce a commanding performance in the 800m freestyle as she booked her second spot on the GB team. Adlington led from the off and was never challenged, winning in eight minutes 18.54 seconds.
Sheffield-based Eleanor Faulkner, 19, set a personal best of 8mins 27.11secs to also claim a place at the Games. Adlington, though, revealed she had suffered from such intense nerves before the race she had to speak to her psychologist Simon Middlemass.
Adlington: “I was more nervous for some reason today, I think it’s because this event means so much to me.”
Michael Rock came back on the second length to qualify for the 100m butterfly in 52.02.