As BAR and Japan jockeyed for position before the start of the final race on day one of the qualifying series, Japan skipper Dean Barker aggressively challenged his rival for inside running and counterpart Sir Ben Ainslie did not react quickly enough.
The boats made heavy contact, with BAR incurring a split to its hull. The British were penalised, but continued around the course, eventually losing by 48 seconds.
They face a huge job fixing that damage for their next race - they have Oracle Team USA in tomorrow's third race, followed by Emirates Team New Zealand later in the day.
Rookie helmsman Peter Burling had Team New Zealand on the board early in the America's Cup qualifier series, romping home over Team France in their first race off Bermuda this morning.
At 26, Olympic 49er champion Burling is the youngest ever America's Cup helmsman, but gave wily French counterpart Franck Cammas a sailing lesson, controlling the start and rocketing away to lead by one minute 13 seconds by the third mark.
By contrast to their opponents, Emirates Team New Zealand sailed a smooth race, staying on their foils through most of their journey to eventually prevail by two minutes 33 seconds. The Kiwis had crossed the finish line before France had rounded the final mark.
But Team NZ conceded bragging rights against America's Cup rivals Oracle Team USA in their second hit-out, dropping their first head-to-head meeting with the holders.
After their disastrous capitulation in the cup regatta in San Francisco four years ago, the Kiwis would have been intent on gaining an upper hand early.
Emirates Team NZ made a key change to their crew for their second race of the day, bringing Olympic cyclist Simon van Velthooven on board for former rower Joe Sullivan to add grunt to cycle-grinding station.
Oracle skipper Jimmy Spithill held the slight early advantage, establishing a five-second advantage at the second mark.
As both teams jockeyed for position down the third leg, TNZ tacked the better and moved past their archrivals to build a 20-second buffer by the next mark.
But down the fifth leg, the Americans came back strongly and almost drew contact with the NZ boat, as they rounded the fifth mark. That proved the crucial moment, with Oracle easing away for a six-second win.
Race results
R1: ORACLE TEAM USA beat Groupama Team France 2mins and 11 secs
R2: Artemis Racing beat Softbank Team Japan by 13 secs
R3: Emirates Team New Zealand beat Groupama Team France by 2 mins and 33 secs
R4: Land Rover BAR beat Artemis Racing by 11 secs
R5: ORACLE TEAM USA beat Emirates Team New Zealand by six seconds
R6: Softbank Team Japan beat Land Rover BAR by 48 seconds.
