VALENCIA, Spain — America's Cup defender Alinghi sailed by the book yesterday — the Swiss yacht grabbed the lead and defended it.

The defending champion's 30-second victory over New Zealand evened the best-of-nine series at 2-2 for the Auld Mug, the oldest trophy in international sport, and was a classic example of America's Cup racing.

The Swiss built a slight edge and then — as sailors say — "put their elbows out" to block any attempt the Kiwis made to pass.

"It was a lot more classical than yesterday. Yesterday was not a match race," said Ernesto Bertarelli, the Swiss biotech billionaire who founded Alinghi in 2000 and was aboard as a crew member. "It's 2-2. We need to win five, that's all that matters."

The Kiwis lodged a protest after the race when the Swiss dropped their mainsail while a crew member was aloft, contrary to the rules. Regardless of the jury's decision this morning, the Kiwis can expect the move to add more fire to the developing rivalry associated with the tightest America's Cup in 24 years.

"For us," Kiwi crewman Don Cowie said, "the America's Cup starts Friday" — the next day of scheduled racing.

The past three cups have been 5-0 sweeps. The current regatta is guaranteed to be the closet since 1983, when Australia II beat the U.S. boat Liberty 4-3 to take the trophy away from the United States for the first time since the regatta's namesake America won the first competition in 1851.

After the nearly continuous lead changes that occurred Tuesday because of the shifting winds, the racing yesterday followed a more classic script — the trailing boat had to hope for the leader to make a mistake or stall in an area of low wind.

The Swiss won the start yesterday about one second ahead of the Kiwis. The two 80-foot carbon-fiber yachts sailed upwind in a test of pure speed, with Alinghi increasing its lead to 20 seconds as it rounded the first marker buoy to set off on the second, downwind leg.

The Kiwis and 34-year-old skipper Dean Barker made small gains until they lost time when their enormous red spinnaker became tangled. Alinghi lost ground approaching the second mark, but still passed the buoy 34 seconds ahead.