Lauren Boyle has produced an outstanding second half of her swim to claim the 800 metres freestyle at the FINA World Cup in Tokyo.

Boyle swum on the shoulder of world record holder Mareia Belmonte of Spain for close to half the race, before taking the lead at the 350-metre mark.

The 25-year-old Kiwi then powered clear to eventually finish the race by more than two seconds ahead.

It's Boyle's third victory midway through the six-meet cluster of World Cup events.