SAN FRANCISCO — The America’s Cup has produced no shortage of strange scenes in its 162 years. There have been capsizings, shattered masts and shattered spirits, but it has never produced a reversal of fortune quite like this year.

A week ago, the defender of the trophy, Oracle Team USA, bankrolled by the American billionaire Larry Ellison, trailed by eight races to one and was just one defeat from losing the most prestigious prize in yachting to the challenger, Emirates Team New Zealand.

But by winning seven races in succession, including two on Tuesday, Oracle has tied the series at 8-8. Winds permitting, the rivals from different hemispheres will contest one final race Wednesday, winner take all.

Perhaps Ellison, one of the world’s richest men, should have had the event won from the start. As the owner of the defending champion, he got to select where the race would be and what type of boats would be used. He designed a boat so technically advanced and expensive that only three other teams signed up to challenge it, a low figure attributed to the global economic downturn.