Fran Halsall came back from the disappointment of last night's relay failure to reach the 100 metres freestyle final.
The City of Liverpool swimmer swam the final leg of the 4x200m semi-final last night but was unable to bring home a final spot.
However, she hit back this morning with a time of 53.94 seconds - 0.01 slower than her British record in the heats yesterday - to qualify fifth fastest.
"It was a bit harder than last night," said Halsall. "After the relay I was physically and emotionally drained so to get in and do another 53-point this morning was great.
"I have got a night off now so I can get focused and ready for tomorrow morning."
Gregor Tait booked his spot in the 200m backstroke for the second consecutive Olympics by finishing fourth in his semi-final in a time of 1:56.72, just short of a British record.