World No.1 Jason Day is optimistic about his green jacket claims after defending champion Jordan Spieth opened the door with a late collapse in round three at the Masters.

At one stage looking like he would need a near miracle on Sunday, Day will now start the final round just three shots back in a tie for fifth and with confidence he can reel in one of his main adversaries.

“I am really looking forward to it,” Day said.

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“It’s always fun to play Sunday in contention and Sundays at Augusta are a different story.

“I know it is going to be a tough battle, and there are plenty of other good players in contention, so I just have to worry about myself and if I do that and do my best I’m confident I can be there over the last few holes.”

High wind gusts of up to 40kp/h continued to buffet Augusta National on Saturday, making the slick greens ridiculously tricky, but Day managed a one-under 71 to move to even-par 216 for the tournament.

World No.2 Spieth sensationally dropped three shots in his final two holes to rejuvenate the chasing pack.

The Texan was cruising at six under with two to play only to slice drives into the trees on the final two holes, leading to a bogey and double bogey.

Spieth’s 73 left him at three-under 213, one clear of upstart US PGA Tour and Masters rookie Smylie Kaufman (69) at two-under.

Incredibly, 58-year-old two-time Masters champion Bernhard Langer, who won his second green jacket before Spieth was born, is one-under after a round of 70, joined by Japan’s Hideki Matsuyama (72).

Dustin Johnson (72) and Danny Willett (72) join Day in fifth at even par.

Spieth victory would see him match greats

Jordan Spieth’s bogey, then double bogey, on the last two holes as set up a final-day showdown. Photo: Getty

Spieth is looking to be just the fourth player to win the green jacket in back-to-back years after Jack Nicklaus, Nick Faldo and Tiger Woods.

Day’s round was highlighted by a brilliant 70-foot birdie on the 14th hole after he recovered from a drive into the woods.

While he needs to make up ground, he insisted he must find a way to remain calm on Sunday.

He was just two back starting Sunday in 2013 and had the lead after an birdie, eagle start.

By the 16th tee, he led by two shots but made bogey on 16 and 17 to make way for Adam Scott.

“The last three days have been really tough. I’ve been trying to just stay in it for the most part, just trying to stay patient,” Day said.

“It’s always hard to have the lead at a major championship with these conditions, to keep pressing forward.

“So I just kept on saying to myself, `just keep grinding out, just keep trying to get your birdies when you can, minimise mistakes, and just be patient with yourself’.

“I need to kind of show a little bit more patience tomorrow, even though I’m going to have scoring opportunities, I don’t want to make mistakes.”

Scott’s tilt is effectively over after he battled his way to a three-over 75 to drop to a seven over, currently 10 shots adrift.

Masters rookie Cameron Smith opened his third round with a double bogey and it was a battle from that point on, shooting an 82 to fall to 13 over.

-AAP