AUGUSTA, Georgia, April 7 (Reuters) - The birdie roars

finally returned to the Masters in Saturday's third round as

three-times champion Phil Mickelson made an electrifying run

after the turn to charge into contention.

The American left-hander, who has long been inspired by the

iconic Augusta National Golf Club, eagled the par-five 13th on

the way to a six-under-par 66, covering the back nine in a

scintillating six under.

Red numbers had been relatively sparse on the leaderboard

earlier in the day but Mickelson changed that with a stunning

par-birdie-eagle stretch around Amen Corner in dazzling sunshine

before finishing one stroke off the pace at eight-under 208.

"This was a really fun day and it gives me an opportunity to

make something special happen tomorrow," a perpetually smiling

Mickelson told reporters after moving into position to clinch a

fifth major title. "There's nothing more exciting than being in

the final group on Sunday at the Masters."

Mickelson sparked the biggest roars of the day after he cut

a six-iron from 206 yards into the 13th green, his ball settling

20 feet short of the hole from where he sank the curling putt.

"I've hit that putt so many times over the years and just

knew that that ball was going to curl in sideways," the

41-year-old said. "I knew it was slow up that hill, and the ball

just crept over the lip. It was a great feeling to see that one

go. That was a big momentum change right there."

SIGNIFICANT MOMENT

Mickelson, who won the most recent of his three green

jackets at Augusta National in 2010, felt his most significant

moment this week came in the opening round when he fought back

from after four over par 10 holes.

"I felt like at some point I would get hot, kind of like the

back nine today," he said. "But instead of being just enough to

make the cut, I wanted it to be something where it could move me

up the leaderboard.

"So I had to really fight on Thursday when I was letting the

round slip away. Getting a couple of shots back on Thursday

evening is what put me in a position to shoot a low round and

move up the leaderboard."

Mickelson, who says he is putting better than ever, was

especially pleased with his birdie at the par-five 15th where he

executed a stunning flop shot from a flat lie behind the green,

with a full swing, to just four feet.

"It wasn't the safest shot, and that's not where I want to

be," he said. "That pin position is by far the toughest for me

to make a four on that hole, because you can't miss short;

you're in the water.

"And long is no bargain, the way the green is pitched

severely from back to front in the middle; that's not where I

wanted to be. That spot that was a very tough up and down."

Mickelson will go into Sunday's final round a stroke behind

pacesetting Swede Peter Hanson, his playing partner for the

first two rounds this week.

(Reporting by Mark Lamport-Stokes; Editing by Frank Pingue)