Australian skipper Jimmy Spithill's Oracle Team USA have made a flying start on the first day of the America's Cup in Bermuda.
Oracle comfortably defeated Groupama Team France and then came from behind in their second race with a narrow victory over arch rival Emirates Team New Zealand.
Spithill is accompanied by Oracle's trimmer-tactician Tom Slingsby, who won a Laser class gold medal for Australia at the London Olympics in 2012.
After spending years designing and building their 50-foot (15 metre) foiling catamarans, all six crews competing for the 35th America's Cup were in action on Saturday and racing was as hotly contested.
Conditions in Bermuda's Great Sound were near perfect for the head-to-head "match racing", with winds of 10-12 knots and perfect flat water allowing the high-tech catamarans, which can reach speeds of up to 50 knots (92.6 kilometres per hour).
British challenger Land Rover BAR comfortably won against Sweden's Artemis Racing, who had been showing great speed in the run up to the qualifying races.
But Ben Ainslie's crew then lost to SoftBank Team Japan in the final race of the day after a spectacular high-speed collision between the two catamarans, which have taken huge design teams and millions of dollars to develop.
Ainslie was penalised for not having taken evasive action when Japan had right of way before the two crossed the starting line and there were signs of damage to the outer skin of his boat's high-tech carbon fibre hull, which appeared to narrowly miss several of SoftBank Team Japan's six-man crew as it lurched dramatically in the air as the two boats came to blows.
Oracle Team USA, who are defending the cup they won in San Francisco in 2013, showed their intention early by getting the better start against the French and quickly demonstrated superior speed as their catamaran lifted out of the water.
Spithill's team reached speeds of at least 42 knots as they left the French crew in their wake in their first race.
They also took an early lead against the New Zealand team, before losing ground and then having to take a tactical gamble to get back in front.
The New Zealand crew, using a revolutionary cycling set-up to power the hydraulics on their boat, showed speed and manoeuvrability but as the two catamarans screamed towards the grandstand at the finish, they trailed the US by six seconds.
