The fourth leg of the Volvo Ocean yacht ace gets underway Sunday with two former crewmates expected to battle for supremacy between New Zealand and Brazil.

American Paul Cayard has joined the crew aboard Amer Sports One while his former America's Cup teammate John Kostecki is the skipper of the German boat Illbruck, the current leader.

Kostecki will also have to fend off former EF Language teammate Mark Rudiger who is on board the boat Assa Abloy, which won the leg from Sydney to Auckland.

The fleet heads to Rio de Janeiro, a 6,700 nautical mile journey before turning northward to the United States. The race ends in Kiel, Germany in June.