Emirates Team New Zealand outsailed billionaire Larry Ellison’s Oracle Team USA in the first day of the America’s Cup finals with near collisions and a man overboard as the high-tech catamarans criss-crossed San Francisco Bay in the first close-fought duels since the regatta began two months ago.

Manoeuvering his 72-foot carbon-fibre yacht at speeds close to 45 miles per hour, Emirates Team New Zealand skipper Dean Barker aggressively cut off Cup defender Oracle’s boat several times to win the first two races in the best-of-17 final series.

Already hobbled by a cheating penalty, the results make it even harder for Oracle to defend the Cup it won in Valencia in 2010 and brought to San Francisco.

The final series of matches is the culmination of a regatta plagued by controversies including cheating by Oracle, dangerous catamarans, a fatal accident and accusations of mismanagement.

Fans along the shore at an America’s Cup park on San Francisco Bay cheered the Kiwis as their AC72 catamaran crossed the finish line with a lead of nearly a minute in the day’s second race.

Seconds before the first race, an Oracle crewman fell overboard, leaving his team to compete with only 10 sailors.

New Zealand began that match with a small lead and was passed by Oracle for a short time before regaining its lead and winning by 36 seconds.

“Hopefully, we can take some races and not have passes and just win,” Oracle tactician John Kostecki said at a post race press conference, when asked if the boats were evenly matched.

In pre-start manoeuvering of the second race, the two boats appeared to touch each other as Oracle went for a controlling position just downwind of the Kiwis. Even a light collision could have cost New Zealand a penalty, but none was called.

Bookmakers see the Kiwis as favourites to take the America’s Cup from Oracle.

Due to the penalty, Oracle needs to win 11 races to retain the Cup, while New Zealand only needs to win a total of nine.

With Saturday’s two victories, New Zealand now needs seven more.