Luna Rossa are on course for a shock series win over Oracle

The Luna Rossa crew raced to a 4-1 lead after winning by one minute 57 seconds in the best-of-nine series on Saturday.

In the other semi, Team New Zealand beat Spain's Desafio Espanol by 1:49 to also edge to a 4-1 lead.

The Louis Vuitton winners will face Swiss defending champions Alinghi for the America's Cup from 23 June-7 July.

BMW Oracle skipper Chris Dickson picked up two quick penalties in the complicated pre-start manoeuvring, meaning his boat had to perform two complete turns on the race course.

We may decide to make a change just to shake things up BMW Oracle's Chris Dickson

Kiwi Dickson took one penalty after the start and the second just before the finish line but Luna Rossa's Australian skipper James Spithill was easily able to defend his lead.

"It was a disappointing pre-start for us and Luna Rossa did a good job of maintaining their starboard advantage," said Peter Isler, navigator of the BMW Oracle team which is bankrolled by software billionaire Larry Ellison.

"We risked it and it went bad for us. We must now win every race. We will see what we can throw at Luna Rossa. Don't count us out yet."

Isler said his team would consider making changes to the crew after being dominated by the Italians, who have led around every marker in the series.

"They've earned their victories," Isler said. "Now we may decide to make a change just to shake things up, but we'll see later."

Luna Rossa won the Louis Vuitton Cup in 2000 but went out at the semi-final stage in 2003.