There will be British representation in an Olympic synchro final for the first time in 20 years after Jenna Randall and Olivia Federici qualified in ninth for the duet, as Russia close in on their fourth consecutive gold.
In Beijing, the pair had been the first Britons to compete at a Games since 1992 where they finished 14th.
In the intervening four years, the pair have made huge strides on the world stage, including a Commonwealth silver medal together, and now they will be the first British synchronettes in an Olympic final since 1992 when Kerry Shacklock and Laila Vakil finished sixth.
The free routine is marked on artistic impression and technical merit, with a maximum mark of 50 points for each.
These are then combined and added to the result of yesterday's technical routine, with the top 12 of the 24 pairs going through.
Randall and Federici - who both train at the high performance centre in Aldershot - had yesterday improved by one their 10th-placed finish at last year's World Championships in the technical routine.
Today their London-themed free routine portraying the ravens at the Tower of London set to a Chemical Brothers soundtrack was scored 88.790 points, placing them ninth today, one down on eighth in Shanghai last summer.
When combined with their technical result yesterday the pair went through with 176.890pts, and insisted they had plenty to work on before tomorrow afternoon's final.
Randall said: "We've got a few things to improve on for tomorrow, it wasn't one of our best so we are hoping to get the things fixed we need to get fixed and make an improvement.
"With the technical aspect of our routine, there were a few things that were slightly off, we weren't exactly the same so just to try and make that perfect tomorrow."
Federici echoed her team-mate's sentiments, saying: "We want to go back home, look at the video, see what we can do so when we get back in the pool and train tomorrow, and really make it a perfect swim so we give our best performance.
"This is our London 2012 Games so we want to give it everything we've got and do our best performance of the year."
When the pair competed at the European Championships in Eindhoven earlier this year, it was felt the scoring was questionable.
Randall said: "The important thing we've got to think about is that synchro is a very judged sport - all we can put in tomorrow is our best performance so we know we have done the best we can do so hopefully the judges will reward us with good marks.
"Our reputation as a country is improving and the judges are seeing that we are improving at every competition we go to."
Russia have dominated synchronised swimming since winning their first gold at Sydney 12 years ago and they are the clear favourites here.
Their technical routine was judged to have been just 1.800 off perfection yesterday.
Today the pair of Natalia Ischenko, dubbed "Phelps in a skirt" thanks to her accumulation of world titles like the now-retired swimmer, and Svetlana Romashina concluded a nigh-on perfectly executed, haunting routine to the music of the film Sleepy Hollow.
The judges awarded them a total of 98.600 which when combined with yesterday's mark gave them an overall result of 196.800 out of 200.
China go into the final second with Spain third.
Ischenko said: "Today we are maybe about 90% happy. We have small things to fix for the final.
"I hope the judges did not see the mistakes our coach saw."
Romashina also revealed Russian athletes have been given instructions from the top.
"(prime minister) Dmitry Medvedev has given the order to all athletes that they are not allowed to shop or walk around London.
"We only relax in the Olympic village," she joked.
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