AUCKLAND, New Zealand -- Oracle of San Francisco moved within one victory of the America's Cup challenger final Sunday when it took a 3 to minus-1 lead over Seattle's OneWorld Challenge in the semifinal repechage.

OneWorld incurred an early penalty for a right-of-way infringement and fouled again when it crossed the startline before the gun.

Those errors gave OneWorld little hope of saving the race and preventing Oracle from taking a big lead in a best-of-seven series. It followed Oracle around the 18.5 nautical mile course and, when it had discharged its penalty at the finish line, trailed by 55 seconds.

Oracle has won the three repechage races to date -- by 4:08 Friday, three seconds Saturday and by Sunday's comfortable margin. It needs only one more win to join Switzerland's team Alinghi in the final starting Jan. 11.

Oracle's strongest asset in the series has been its strong defensive performances against a talented opponent in shifty conditions. It showed that quality again Sunday, holding out OneWorld on the last two legs to cross the finish line 23 seconds in front before its rival had completed its penalty.

The startbox errors by OneWorld, both additions to a growing list of tactical mistakes, decided the race before it had begun.

"It was very shifty today,'' said Oracle navigator Ian Burns. "Either side of the course paid off but if you got caught in the middle you'd lose.

"We were lucky we didn't collide in the pre-start. The boats were very, very close and when they get that close they get sucked together,'' he said. "The penalty wasn't the end of the race. It these conditions things can change very quickly. Sometimes they were in front but each time the shifts went against them.''