Only one challenger has won the 165-year-old yachting competition on its first attempt -- Swiss syndicate Alinghi in 2003.
The UK, which hosted the first series in 1851, has never won the world's oldest continuous international sports event.
While Ainslie earned the headlines, behind the scenes his 130-strong lineup of engineers, aerodynamicists, designers and sailors implemented high-end technology and concepts from the motor industry.
"This one is down to Ben and his sailing team, who have shown they are the class of the field in one-design sailing boats," says Richard Hopkirk, engineering manager at Land Rover BAR.
Hopkirk, a Cambridge and Harvard University graduate, knows all about defying the odds.
In 2007, he was a race tactician in the pit lane at the McLaren Formula One team, working with a young driver called Lewis Hamilton. A year later, Hamilton became F1's then youngest champion at the age of 23.
Hopkirk now heads up a team of 25 people trying to predict the performance of Ainslie's futuristic-looking catamaran with its towering wing sail.
He says there are a lot of similarities between racing cars and boats.
"In both cases you have to understand the core physics and behavior of what you're designing," Hopkirk explains.
He is impressed by the close cooperation between the team's wide range of technical specialists.
"The level of interaction is much higher than I experienced in F1 and it's one of the most enjoyable aspects of the job," Hopkirk says.
'Eking every last knot'
Ainslie's partnership with British car manufacturer Jaguar Land Rover allowed the team to use automotive technology in developing the 45-foot catamaran it used for the World Series.
It is the precursor to the AC50s that will be used in the America's Cup, where BAR will start May's qualifying series with two bonus points as it seeks to win the right to challenge Oracle Team USA in June's championship series.
Land Rover BAR expects to launch its AC50 -- which should have a top speed of around 55 miles per hour, the quickest in sailing history -- at the end of January or early February.
The boat's wing sail, similar in size to the wing of a Boeing 737 airliner, stands atop a lightweight carbon-fiber catamaran equipped with hydrofoils that allow the hulls to rise up and glide over the water instead of battling the waves.
At the team's base in Portsmouth on England's south coast, engineers have been applying knowledge gained from developing cars to "eking every last knot" out of the wing sail, says Ian Anderton, Jaguar Land Rover's senior manager of thermal and aerodynamics systems.
The computer-controlled wing sail is what powers the boat forward, and the next six months of testing will be crucial.
Because the winds are expected to be lighter in Bermuda, the test boats have been optimized for performance in the new conditions, meaning they will be on the foils in much lower wind speeds than at home in Britain.
Over the past year, Anderton's team has made "lots and lots of marginal gains" of as little as 0.1 of a knot using a sophisticated computer analysis that simulates how the wing sail and air flow perform in different conditions.
All of those tiny gains all add up, and may eventually help bring the "Auld Mug" home to Britain for the first time.
"If you have a very slightly on average higher speed than anyone else can achieve in any condition, then you are giving yourself a competitive advantage," says Anderton, who added the AC50 will be capable of foiling all around the course without having to stop at the turns -- unlike the 2013 America's Cup boats.
"We are really focused on delivering that optimum response of the wing sail," Anderton said. "All of our efforts are going into that at the moment."
Relocation to Bermuda
Though the team has a big focus on technology, there are also very human factors involved in its Bermuda mission.
With half the staff relocating to the Caribbean island -- a move that involves 42 containers of equipment, one crane and two boats, as well as rehousing 54 family members, including 30 children of which six are babies -- communications will become even more important.
Land Rover BAR's Portsmouth headquarters will remain "mission control" -- with the assistance of a communications system also used in F1 that allows engineers and performance analysts to track the two test boats doing practice runs on the Great Sound in Bermuda in real time as they send back data from more than 190 sensors and four cameras.
Although Ainslie was part of the Oracle USA team that overcame an 8-1 deficit to successfully defend the 34th America's Cup in San Francisco in 2013
, running his own £80 million ($101 million) syndicate has been a completely different ball game.
"For a new team, it's been incredibly tough," Ainslie told the BAR website after clinching the World Series in Fukuoka, Japan in November, having won four of the competition's nine legs.
"We've had to create that infrastructure, build those relationships in a relatively short amount of time compared to our opposition."
"Only one team has won this competition on its first attempt and they achieved that by employing key personnel from the team that had won the previous Cup," Hopkirk says. "It takes a lot to build this kind of technology from a standing start and we have some very experienced competition. We are not complacent."
But if anyone can pull it off, it may be Ainslie, one of only two Olympic sailors to win four gold medals.
"He's an incredibly astute person and he's an incredibly talented sailor," says America's Cup CEO Russell Coutts
, the most successful helmsman in the competition's history whose 14-0 record in the 1995, 2000 and 2003 editions has never been matched.
"And he's got an excellent team around him."