Lauren Boyle made it a double victory in the penultimate stop of the FINA Swimming World Cup in Doha.
The New Zealand swim star has won the 400m freestyle to back up from winning the 800m freestyle yesterday.
Boyle produced a slick start, hitting the front at the 100m mark and was never headed, winning in a slick 4:06.58 from Great Britain hope Jaz Carlin who was also runner-up to the Kiwi in the 800m freestyle.
It is a positive indicator for the double world championship medallist at the start of her competition season, coming out of a long build-up phase in training.
Frenchwoman Coralie Balmy led at the 50m mark but faded to third with Carlin 1.8s behind at the 200m mark and from there Boyle controlled the race.
Howick Pakuranga sprinter Daniel Hunter finished seventh in the men's 50m freestyle final in 22.82, which is half a second outside the Rio Olympic qualifying standard in the race won by Brazilian Bruno Fratus in 22.28s.
Swimming New Zealand high performance squad swimmer Nathan Capp was ninth fastest in the 1500m freestyle in 15.30.49 won by Mykhailo Romanchuk (UKR) in 15:07.06.
The final leg of the world cup will be in Dubai at the weekend.
Day 2 finals:
Women 400m freestyle: Lauren Boyle (NZL) 4:06.58, 1; Jaz Carlin (GBR) 4:07.42, 2; Coralie Balmy (FRA) 4:07.56, 3.
Men 50m freestyle: Bruno Fratus (BRA) 22.28, 1; Anthony Ervin (USA) 22.47, 2; Douglas Erasmus (RSA) 22.50, 3. Also: Daniel Hunter (NZL) 22.82, 7.
