New Zealand sailors Peter Burling and Blair Tuke have claimed a third consecutive 49er World Championship title.
Burling and Tuke secured the championship in Buenos Aires before Sunday morning's final medal race, in which they finished fourth.
The Olympic silver medallists - London 2012 was the last time they lost - took a 12-point lead into the final day, and the recently-named 2015 ISAF Rolex World Sailors of the Year extended their unprecedented winning streak in the Olympic skiff class.
Victory in Argentina made it 23 consecutive wins in the 49er class.
Burling and Tuke unbeatable since 2012
The pair of 24-year-old Burling and 26-year-old Tuke had this victory in the bag with a race to spare after opening an unassailable 29-point gap after three morning races in which Burling and Tuke placed 13th, eighth and eighth.
The Alonso brothers from Spain struggled on the last day and were third behind the reigning Olympic champion crew from Australia of Nathan Outteridge and Iain Jensen, who sailed themselves back into medal contention during the morning to edge out the Spanish for the silver medal.
The New Zealanders, described by commentators as being in a class of their own, ended the 16-race regatta 34 points ahead of anyone else.
"We're absolutely stoked to take another title," Burling said. "This one has been a really tough week and I think both Blair and myself are pretty tired now which shows how tough it's been, but we are really stoked to take another title and I'm sure it will set in over the next couple of hours."
"We didn't sail super well today, which we were a bit annoyed about, but at the same time the guys that were close to us sailed worse so we ended up with a pretty huge lead again which is really nice," Tuke said.
"It's really nice to win our third world title, and all in a row."
"Being named ISAF Rolex Sailor of the Year last week was pretty special and we had our heads down concentrating on this trying to get the best prepared we could, so we'll sure enjoy it with our coach Hamish [Willcox] and the rest of the Kiwis here," Tuke said. "Then we'll look forward to getting back to New Zealand and sharing it with family and friends."
Maloney, Meech finish disappointing eighth
New Zealand team-mates Alexandra Maloney and Molly Meech finished eighth in the 49erFX World Championship.
In the final day's morning races they placed second, 14th and 19th to go into the 49erFX medal race lying ninth overall, improving to eighth after finishing third in the medal race.
"I think everyone was a bit up and down, quite a big mixture of people winning races," Maloney said. "The fleet is getting tougher and it was really good competition out there."
"Moving on from here," Meech added. "Obviously Rio's the big goal for next year.
"And the build-up events like the Worlds in Clearwater and then Hyeres, so trying to get on the podium in those events."
Giulia Conti and Francesca Clapcich (ITA) took overall victory in the 49erFX and their first world title after a very close battle with defending champions Martine Grael and Kahena Kunze from Brazil.
The two close rivals entered the medal race on equal points and went on to finish first and second on the water in a grand finale in Argentina.
Burling and Tuke's year in the 49er:
1st - 2015 49er World Championship
1st - 2015 South American Championship
1st -2015 Rio Olympic Test Event
1st - 2015 49er Rio International Sailing Week
1st - 2015 49er European Championship
1st - 2015 ISAF Sailing World Cup Weymouth
1st - 2015 ISAF Sailing World Cup Hyeres
1st - 2015 Princesa Sofia Regatta (Palma)
1st - 2015 Oceanbridge Sail Auckland
1st - 2015 New Zealand 49er National Championships