Lizzie Simmonds claimed her second gold of the Mare Nostrum meeting in Canet-en-Roussillon as Great Britain took their medal tally at the two-day event into double figures.
The 21-year-old Loughborough swimmer led from start to finish in the 200metres backstroke, clinching victory in two minutes 8.94 - over three seconds clear of Holland's Femke Heemskerk (2:12.25).
Simmonds also secured silver in the 50m backstroke, her time of 28.62secs just one hundredth of a second behind Australia's Sophie Edington.
Elsewhere, Loughborough University's Amy Smith picked up gold in the 100m freestyle ahead of Sweden's Michelle Coleman (55.15s), while Liam Tancock's 25.36s was good enough for bronze in the 50m backstroke final behind France's Camille Lacourt and Australia's Ben Treffers.
The Loughborough man's fellow Briton Chris Walker-Hebborn (Bath) was eighth in 26.06s.
Bath's Andrew Willis (100m breaststroke) and Millfield's Joel Knight (1500m freestyle) finished fourth in their respective events, while James Guy (Millfield) was fifth in the 200m butterfly and Grant Turner (Loughborough) eighth in the 100m freestyle.
France's Camille Muffat won the 400m freestyle in a meet record 4:02.97, with Britain's Lucy Ellis seventh (4:16.93).