Sarah Sjöström of Sweden and Hungary's Katinka Hosszú each picked up two gold medals on the second day of the International Swimming Federation (FINA) World Cup in Doha.
Between them they won all but one of the female events on the schedule, with Hosszu winning the 400 metre individual medley and 100m backstroke, while Sjöström triumphed in the 200m freestyle and 50m butterfly.
Hosszú took the first final of the evening, the 400m individual medley, in a time of 4min 39.57sec, beating compatriot Zsuzanna Jakabos, who finished five seconds behind.
She also claimed victory in the 100m backstroke in a time of 59.63sec, while Kira Toussaint from the Netherlands came second in 1:00.05.
Sjöström, the seven-time world champion who won Olympic gold at the 2016 Games in Rio de Janeiro, defended the two titles she also won on the first World Cup stop in Kazan.
The 25-year-old took the 200m freestyle title first in 1:56.32, ahead of Femke Heemskerk who clocked 1:56.92, and Hosszu in 2:00.16,
She then won the 50m butterfly in a World Cup record of 25.39.
The only other record of the night came in the men’s 100m freestyle, in which Blake Pieroni from the United States won in 48.11, lowering South African Chad Le Clos’ 2015 mark of 48.16.
Action in Doha continues tomorrow.