John Cutler believes Desafío Español have closed in on the big three but is reluctant to commit any further.

"I am fully aware how much extra resources either in people, experience, money or time those teams have over what we have had available to us," he said.

"It is still a very big hurdle to step from a team that has been together for two years to take on a team like Oracle, who has been going for a while and Team New Zealand that has been going for a very long time and Luna Rossa who have been rolling along for a while too".

"The distance between us is getting smaller but have we made the step up to that level? We'll only know that at the end of the event."

Desafío Español are the fourth Spanish team to challenge for the cup since 1992. However, this 2007 team represents a breakaway from past teams.

While the sailing team features mostly Spanish sailors, it also includes an international afterguard including Cutler (tactician), Poland's Karol Jabolonski (helmsman) and American Matt Wachowicz (navigator).

They also hired American sailing legend Paul Cayard as a consultant. His contract expired at the end of March but Cutler isn't ruling out an appearance by the American at the helm during the challenger series.

"There is always a chance that he will do anything. It would be unlikely but you never say never in the America's Cup."

Cutler says Team New Zealand and his former team BMW Oracle Racing look the most potent of the challengers.

"They are extremely well funded and well organised. They both had a plan of how they are going to do the event. From the outside they are the two teams to beat."

"It will be hard to pick between the [top] two therefore it is going to come down to the guys sailing the boat. Are they going to make a mistakes under pressure, are they going to get the side that the weather teams wants, are they going to get the timing back to the startline correct?"