British duo Kate Shortman and Isabelle Thorpe are fourth in the artistic swimming competition following their opening technical routine on Friday.
Second-last to perform, the Bristol-based pair scored 264.0282 and are half a point outside the medal positions.
Shortman told BBC Sport: “We are going to fight to the death. We really want a medal. We are going to put our heart into it and leave it all in the pool.”
“The swim felt good,” Thorpe added. “It was amazing having a crowd.”
All 18 duets will return on Saturday to perform a free routine, with medals to be decided by a collective score.
GB’s best finish at an Olympics in the sport was fourth, 40 years ago in Los Angeles.
Shortman and Thorpe and Kate have high hopes they can find the routine needed to match their silver medal at the World Championships in Doha earlier this year.