Masterful Spieth moves two ahead at Augusta

The American's love affair with the challenging Augusta National layout continued in flawless style as he fired a six-under-par 66 to storm to the top of a high-quality leaderboard in the first of the year's four major championships.

Bidding to become only the fourth player to claim back-to-back Masters victories, world number two Spieth took advantage of relatively calm morning conditions before coping superbly with tricky gusting winds as he kept his card bogey-free.

"I would have signed for two-under today and not even played the round, knowing the conditions that were coming up," said the 22-year-old Spieth, who is aiming to emulate Jack Nicklaus, Nick Faldo and Tiger Woods with consecutive Green Jackets.

Spieth ended the day two shots ahead of New Zealander Danny Lee and Irishman Shane Lowry, with Englishmen Justin Rose, Paul Casey and Ian Poulter, Dane Soren Kjeldsen and Spaniard Sergio Garcia a further stroke back after opening with 69s.

Rory McIlroy bogeyed the final hole for a 70 while world number one Jason Day, the hottest player in the game after winning six times in his last 13 starts, got to five-under before dropping five shots in his last four holes for a 72.

Shaking off a run of inconsistent form in recent weeks on the PGA Tour, Spieth sank a six-footer at the third, a 13-footer at the sixth and a four-footer at the eighth to reach the turn in three-under 33.

FINISHED IN STYLE

He picked up further shots at the 10th and 13th, sank a clutch 15-footer to save par at the 16th and finished in style by rolling in a six-footer at the last before pumping his fist in celebration.

Spieth became the first defending Masters champion to hold the outright lead after the first round since Jack Nicklaus in 1966.

Casey, who played in Spieth's company, was hugely impressed by the American's 66.

"That was a flawless round of golf," said Casey, who shot a 69 on an increasingly blustery day. "One of the toughest days I've ever seen around Augusta National ... it was great to have a front row seat to watch that."

Spieth won the PGA Tour's Hyundai Tournament of Champions in January, but struggled to string together four good rounds in his next five strokeplay starts before returning this week to the welcome surroundings of Augusta National.

He tied for second on his Masters debut in 2014, then last year stunned the golf world as he completed a wire-to-wire victory by four shots, matching Woods' tournament record low of 18-under 270 for 72 holes.

While Spieth flourished on Thursday, former world number one Ernie Els made a nightmare start as he six-putted from three feet at the par-four first to run up a mind-boggling nine.

It was the highest ever Masters score on that hole and left South African Els, who has struggled badly with his short putting for more than a year, shaking his head in disbelief. He went on to shoot 80, tying his worst round at Augusta.

"It's unexplainable," said Els, a four-times major winner. "I couldn't get the putter back. I've made thousands of three-footers and I just couldn't take it back."

Australian Day, seeking a second consecutive major victory after winning his first at the PGA Championship in August, was just one stroke off the pace until he bogeyed the 15th.

He then triple-bogeyed the par-three 16th after hitting his tee shot into water, reloading and three-putting before he dropped another shot at the 17th.

"It's not the way I planned it out but I felt like I played some really good golf up until then," said Day, who had won on his last two PGA Tour starts before this week.

"Obviously if you get yourself out of position here at this course, it's very difficult to salvage par and unfortunately starting at 15 I got myself out of position pretty good."

Three-times Masters champion Phil Mickelson opened with a 72 while fellow left-hander Bubba Watson, a double winner at Augusta National, faded on the back nine to card a 75.