Alinghi beat Team New Zealand 5-0 to win the America's Cup in 2003

The Swiss syndicate lead 4-2 after a 28-second victory despite trailing for the first two legs.

Alinghi were 11 seconds adrift at the bottom mark but they won a tacking tussle to slide past on the second beat and stayed clear on a tense final run.

Alinghi can clinch the Auld Mug in race seven of nine on Sunday.

"It's a huge win, magnificent," said Alinghi principal Ernesto Bertarelli.

"I'm very, very happy. Today we knew we were behind on the first and second marks, but when our chance came we took it.

"We caught a timely windshift and the crew worked well. We've shown that the first past the first mark does not necessarily win the race."

We're not sailing badly, it's just the crunch decision - the key moment just hasn't gone our way Team NZ skipper Dean Barker

Team New Zealand came out aggressively to make amends for Friday's blown spinnaker, which cost them race five, and skipper Dean Barker set up a classic America's Cup dial-up, where both boats hold still in a face-off.

When the dial-up broke, New Zealand gybed right in front of Alinghi. Swiss skipper Brad Butterworth raised a penalty flag but the referee declined the award.

Both boats sped towards the start line and crossed at the same time but the Kiwis built a 14-second lead at the top mark.

The New Zealanders were still ahead by 11 seconds at the downwind mark, as the boats split to go upwind.

Team New Zealand opted to go around the left buoy and Alinghi went around the right, but the defending champions made the most of better wind shifts and tacked aggressively to squeeze back in front.

Alinghi built a 16-second lead at the final mark and despite NZL 92 pushing hard behind, the Swiss side maintained their advantage to the line.

"We're as positive as we can be - it's hard losing races," Barker said.

"We're not sailing badly, it's just the crunch decision. The key moment just hasn't gone our way."

The Swiss boat swept the Kiwis 5-0 in 2003 to bring the Cup back to Europe for the first time since the inaugural competition 152 years earlier.

But this series is the closest since John Bertrand skippered Australia II past Dennis Connor's Liberty on the final lap for an improbable 4-3 series win in 1983.