Augusta - World No 1 Dustin Johnson and second-ranked Justin Thomas will fight for the top spot as well as a Masters green jacket this weekend at Augusta National.
The American rivals and major champions will settle which of them belongs atop the world rankings come Monday even if neither manages to swipe his first Masters crown, although that's their top priority.
Both share sixth on 3-under par 141 after 36 holes, six strokes adrift of leader Patrick Reed, who was a runner-up to Thomas at last year's PGA Championship at Quail Hollow.
"I feel like I'm in a good position," Johnson said. "There are some birdie holes out there. Conditions are tough, so you're going to have to play a good solid round. I'm in a good spot."
Johnson, the 2016 US Open champion, has spent the past 59 weeks atop the world rankings since ending the reign of Australian Jason Day.
Thomas, who won last year's PGA Championship, missed a chance to overtake Johnson two weeks ago with a WGC Match Play semi-final loss to eventual winner Bubba Watson.
"It's very important to me. It's a huge goal of mine," Thomas said of No 1. "But at the end of the day, if I just continue to play well and be in contention and win tournaments, it's something I feel like that's going to take care of itself."
Johnson doesn't need to win to keep his spot and Thomas doesn't need to win to overtake him.
But Thomas is assured the top spot if he completes the PGA Championship-Masters back-to-back double - a feat achieved only by Phil Mickelson, Tiger Woods, Jack Nicklaus and Sam Snead.
Thomas could finish as low as fifth and still move up provided Johnson finishes lower. And there is the chance Jordan Spieth or Jon Rahm could overtake them both for No 1 with a win and help.
"It is a huge deal," Thomas said. "And when and if it's meant to be, and however long, then it will happen."
Johnson has won twice since being forced to withdraw from last year's Masters after injuring his back falling down a staircase when he was a runaway favorite to claim a green jacket.
"That was a year ago. At this point I don't even think about it," Johnson said. "But, yeah, I'm definitely happy to be back here. And to put two pretty good rounds together is even better heading into the weekend."
But the long-hitting superstar has never cracked par in the third round in six prior trips to the weekend at the Masters. And he could face rain, cold and fierce winds on Saturday.
"Whatever the weather is, we've got to play in it," Johnson said. "That's OK with me. The tougher the better."
A key will be the par-5 holes, which Johnson has played in 4-under over the first two rounds.
"I definitely played the par-5s very well," Johnson said.
Thomas had not cracked 70 in nine prior rounds at Augusta National before firing a 67 on Friday that included six birdies, three in a row starting at the par-5 13th.
"I'm happy to finally shoot a round in the 60s here in tournament competition," Thomas said.
"It was a good day, solid, nothing crazy, nothing out of the ordinary. I just tried to stay patient and understand that the back nine, you can make a lot of birdies where you can kind of get on a little run."
Thomas admits he will be looking at the leaderboards and hoping to make a charge at the top.
"You always want to see your name on that big board, because that means you're doing something right," Thomas said.
"I'll probably do a little bit more watching this weekend, but hopefully come Sunday I'll see my name up there."
Tee times for the third round of the 2018 Masters at Augusta National Golf Club on Saturday (a-denotes amateur):
All SA times
16:00: Paul Casey (ENG)
16:10: Matthew Fitzpatrick (ENG), Kiradech Aphibarnrat (THA)
16:20: Tyrrell Hatton (ENG), Phil Mickelson (USA)
16:30: Webb Simpson (USA), Xander Schauffele (USA)
10:40: Tiger Woods (USA), Ian Poulter (ENG)
16:50: Adam Scott (AUS), Bryson DeChambeau (USA)
17:00: a-Doug Ghim (USA), Bernhard Langer (GER)
17:10: Martin Kaymer (GER), Kim Si-woo (KOR)
17:20: Brian Harman (USA), Daniel Berger (USA)
17:30: Chez Reavie (USA), Kevin Kisner (USA)
17:40: Branden Grace (RSA), Jason Day (AUS)
17:50: Francesco Molinari (ITA), Kyle Stanley (USA)
18:00: Ryan Moore (USA) Jhonattan Vegas (VEN)
18:10: Satoshi Kodaira (JPN), Fred Couples (USA)
18:30: Rafael Cabrera Bello (ESP), Vijay Singh (FIJ)
18:40: Li Haotong (CHN), Russell Henley (USA)
18:50: Tommy Fleetwood (ENG), Adam Hadwin (CAN)
19:00: Hideki Matsuyama (JPN), Zach Johnson (USA)
19:10: Bernd Wiesberger (AUT), Jimmy Walker (USA)
19:20: Matt Kuchar (USA), Jon Rahm (ESP)
19:30: Charley Hoffman (USA), Cameron Smith (AUS)
19:40: Justin Rose (ENG), Bubba Watson (USA)
19:50: Rickie Fowler (USA), Louis Oosthuizen (RSA)
20:00: Justin Thomas (USA), Tony Finau (USA)
20:10: Jordan Spieth (USA), Dustin Johnson (USA)
20:20: Henrik Stenson (SWE), Rory McIlroy (NIR)
20:30: Patrick Reed (USA), Marc Leishman (AUS)