* New Zealand lead U.S. 6-1 in first-to-seven series
* Oracle Team USA skipper says will fight to end
* Kiwis seek to avenge America's Cup final loss in 2013 (Updates with quotes from Spithill)
By Alexander Smith and Tessa Walsh
HAMILTON, Bermuda, June 25 (Reuters) - New Zealand flew to the edge of America's Cup victory over the U.S. on Sunday, going 6-1 ahead in the first-to-seven final and setting themselves up to exorcise the ghost of losing in San Francisco in 2013.
Veteran Oracle Team USA skipper Jimmy Spithill was out-smarted by his younger rival Peter Burling in both races on Bermuda's Great Sound, with Emirates Team New Zealand giving a masterclass in "foiling" their 50-foot (15 metre) catamaran.
"Hat's off to those guys today, they sailed clean and smart," Spithill said after the race, adding that the U.S. team bankrolled by Oracle founder Larry Ellison would fight to the end and had staged a comeback from a similar position before.
"We clearly just made too many mistakes today ... we've got to take this one race at a time now," Spithill said at a media briefing, adding that everything was on the table, including whether he would still be helming Oracle's boat "17".
"I'll do whatever is good for the team... If we think the team has got a better chance with me off the wheel, no problem," he said when asked whether he would be steering on Monday, after admitting to several mistakes during the racing.
Spithill's fightback in San Francisco in 2013 ranks as one of the biggest ever sporting reversals, overturning an 8-1 New Zealand lead to win the "Auld Mug" by 9-8.
The tough-talking Australian sailor and his crew will need to find something special to repeat that feat, after making significant changes in the last week to their space-age catamaran to try to match the New Zealand boat's superior speed.
The Kiwis have revolutionised sailing in the 35th America's Cup, using "cyclors" who pedal to provide the power needed to control the boat's foils and towering "wing" sail.
Burling, a 26-year-old Olympic gold medallist in 2016, was cool and composed as he "luffed" and trapped the more experienced match-racing specialist Spithill in the "pre-start" of the day's second race, forcing the U.S. boat to a standstill.
Such head-to-head duels can often determine the outcome of America's Cup clashes, with New Zealand quickly establishing an early lead which they never relinquished.
"They didn't have many chances to get back in the race," Burling said from on board his catamaran at the finish.
Although the six-man U.S. crew managed to notch up their first victory of the series on Saturday, and appeared finally to be matching the Kiwis for speed, they were less stable when "foiling" above the water.
Every time the catamaran's hulls "touch down" on the water they lose crucial speed and the New Zealand were able to "fly" their cat around the course on the sparkling Bermudan waters 100 percent of the time. (Editing by Ken Ferris)