Italy's Prada Challenge, in a desperate struggle to stay in yachting's Americas Cup today accused rival Dennis Conner of sailing in the challenger semi-finals with an illegal sail.

The protest comes just days after Conner's Stars and Stripes was docked a point for using an illegal Australian rudder.

Earlier in the day Conner, the godfather of the cup, survived elimination by 22 seconds to the despair of Prada who now face sudden death in a yachting equivalent of a golden goal.

The near certain shoot-out between Stars and Stripes and Prada's Luna Rossa on the Hauraki Gulf will take place tomorrow with the winner joining San Francisco's AmericaOne in the finals of the Louis Vuitton Cup starting January 20th.

The winner of that competition then meets Team New Zealand starting February 19th for the Americas Cup. Luna Rossa ended its 10 races with seven points. Stars and Stripes has sailed nine races and has six points.

Stars and Stripes will today sail its make-up race, and more than likely win, against Dawn Riley's America True.

This will tie up the points between Luna Rossa and Stars and Stripes leading to the penalty shoot out race tomorrow with the winner taking all.

The latest protest against Conner centres on a new mainsail, which the syndicate readily acknowledged vastly improved their performance. Prada claims the design and technology knowledge behind the sails is actually the work of Young America, the now-defeated New York Yacht Club syndicate.

Team Dennis Conner trimmer and operations director Bill Trenkle said the accusations were "absolutely not true".

Yesterday's racing started in strong winds and a choppy sea, favouring Stars and Stripes, but during the event the seas calmed and the wind very nearly died.

AmericaOne did not have to sail the race, as it had already qualified, but overnight they had their boat USA-61 re-measured because of unknown modifications below the waterline.

Stars and Stripes, without Conners aboard and helmed by Ken Read, maintained a steady lead at each mark. At the halfway point Stars and Stripes were leading by 13 seconds.

On the last downhill leg Read and Cayard tussled with each other but Read seemed to have it secured and eventually Stars and Stripes crossed the line 22 seconds ahead.