Jordan Spieth, at 20, is sitting on top of the golf world

Spieth shares Masters lead with Mr. Bubba Watson as he tries to become the youngest winner ever.

Jordan Spieth

Jordan Spieth, 20, shot a two-under-par 70 Saturday to tie Bubba Watson for the lead entering Sunday's final day of the Masters. (Jim Watson / AFP / Getty Images / April 12, 2014)

AUGUSTA, Ga. — The man with the most continually shouted first name in golf will begin the final round of the Masters on Sunday in a final pairing with the most frightening of competitors.

A 20-year-old kid who refuses to call him by his first name.

Jordan Spieth respectfully refers to all of his elders as "Mister," which will make him the only person at Augusta National not referring to his co-leader as "Bubba."

"Yeah, 'Mr. Watson,' for sure," Spieth said, pausing, smiling. "Just because it'll mess with him."

He's messing with everyone, this kid who looks as if he should be howling from a Cancun balcony on spring break instead of shooting a two-under-par 70 — while Watson was shooting a 74 — to tie the 2012 Masters champion for the lead entering Sunday's final day.

When told he would be addressed like an old man for his next four hours of golf, Watson returned the smile.

"That's fine — when I'm hitting it past him," he said.

It's going to be quite the duel, Bubba against bubble gum, a green jacket against a greenhorn, Iceman against Maverick. When the tournament began, some worried that with no Tiger Woods in the field, there would not be a main attraction on the final day.

Turns out, there are two of them, and although they sit atop a leaderboard that features 11 other guys within four strokes, it's going to be hard to watch anyone else.

If the baby-faced Spieth triumphs, he will be the youngest winner in Masters history and the first golfer to win this tournament in his first try in 35 years. If the weary-looking Watson wins, he will be only the eighth golfer to win two Masters in a three-year span.

It's a standoff that couldn't wait for Sunday, actually beginning early Saturday evening in the interview room, starting with the "Mister" messing and picking up steam.

"Tomorrow is about seeing how I can control my game and emotions out on the golf course against guys that have even won here recently," Spieth said. "Doesn't necessarily mean, I don't think, that they had an advantage in any way."

Bubba Watson doesn't have an advantage in that he pulled off a dramatic win here just two years ago? Watson sighed.

"He's young, nerves are no big deal to him," said Watson. "I've won one, so I've got that going for me."

As if one couldn't already tell, they have arrived in this same revered place from very different directions.

Watson began the round with a three-stroke lead, stretched it to five after two holes, then lost it all in about an hour. The likable guy with the baggy shirts and booming drives had talked earlier in the week about having finally overcome the expectations that accompanied his 2012 Masters win, yet, all at once, he seemed to again be swallowed up in them.

His swings were tight. His putts were short. He had five bogeys, he had two three-putt greens after going 250 holes without a three-putt, he lost all momentum, and only a saving par putt on the final hole kept him from losing the lead.

"We are all going to be nervous and we all know what it means to our career," Watson said. "So it's going to be tough for everybody, not just the guys that have never won one."

Although there is nothing more exciting than growing Augusta cries of "Hey, Bubba!" there perhaps is nothing more disheartening than what happened when those cries faded Saturday into a gaggle of muted "Oh, Bubba."

"We didn't hear anything," Michael Greller, Spieth's caddie, said with a grin.