Five-time Paralympic champion Ellie Simmonds began the night in the pool in Rio with a bronze medal for the 400m freestyle on day six.
The 21 year old former Loughborough College student had clocked a world record and claimed the fifth Paralympic gold medal of her career after triumphing in the 200m IM SM6 at the Games a day earlier.
Simmonds qualified third fastest for the final, where her main rival for gold was set to be Ukraine’s world record holder Yelyzaveta Mereshko.
“That was a decent heat swim,” said Simmonds afterwards. “I'm quite pleased with that. It can be hard work to race again the next day after winning but I went back to the apartment and focused on what I had to do today.
“It's a tight field in the 400m free and I'm going to prepare the best I can for that final.
“I’m really looking forward to racing her, it’s going to be such a tough race.”
Simmonds was unable to defend her titles from Beijing 2008 and London 2012 in the final, touching the wall in 5:24.87 with Mereshko winning gold.
“I don’t really know what happened, I just didn’t have anything at all in me tonight.
“I had a great warm up then I don’t know what happened. I’ve been in good form, but it wasn’t what I wanted at all. It was a lot slower time than I’ve been training before, it wasn’t good.
“It was just one of those days I think, after last night maybe, doing a world record and having a late night, but normally I can do that - I just don’t know what happened.
“I love the 400m freestyle, it made me qualify for the Paralympics in 2008, that’s the event I qualified in. I’ve been unbeaten for a long time but I just wasn’t good enough.”