Jon Rahm has won three PGA Tour and six European Tour events -12 J Rahm (Spa); -8 T Finau (USA), R Palmer (USA); -6 D Willett (Eng) Selected: -5 J Day (Aus), H Norlander (Swe); -4 M Wallace (Eng); -2 R McIlroy (NI), J Spieth (USA); -1 M Fitzpatrick (Eng); +2 T Woods (US)
Spain's Jon Rahm will take over the world rankings if he can turn his four-shot lead into victory in The Last Sunday's round at the Memorial Tournament.
Rahm hit four birdies in a row from the 13th when he hit a four-under 68 to lead 12 on the Americans Ryan Palmer and Tony Finau, who had 73s.
The English Danny Willett is fourth out of six under 70 in Ohio.
World number one Rory McIlroy was second behind a 72, while Tiger Woods had a 71 to improve to two above par.
The 15-time champion, who complained of a bad back for Friday's second round, said he "Moved better" on Saturday.
"It is like this now, I felt like I was doing the first day," added 44-year-old Woods, who won the tournament hosted by Jack Nicklaus in Muirfield Village five times. a record.
For McIlroy, it was a day of one shot won, one returned. He made a hole on five occasions, only to bore the next.
Finau disappears as Rahm drives away
Joint night leader Finau left a 50-foot birdie pit on the 12th and rolled in on the 12th to release four van Rahm at 12 under par.
However, the American double bogeyed the par-three 12th after a foul tee was shot in the rough. Rahm, who played in the group ahead, birded the 13th and the lead was reduced to 1.
The 25-year-old then ran birdie wells on the next three holes while Finau capitulated.
He inexplicably tried to drive the 14th green and found the water, which led to another bogey, and after picking up a birdie on the par-five 15th, he dropped two more shots fall on the 17th after another errant ride.
Rahm, who closed with two pars to get the joint lowest score of round three, will become the world ranking if he wins on Sunday and McIlroy will not finish second jointly. He can also take first place when he finishes second, McIlroy is outside the top 30 and Justin Thomas doesn't win.
He would only become the second Spaniard to top the rankings, after Seve Ballesteros.
"I have to think about good work," he said.
"The plan is to do the same again, fairways and greens and if I can hit the ball on the green up to 30 feet, I have a chance of winning."
Palmer, who led with Finau overnight, dropped two shots in the final three holes to drop back to the level of his fellow American.
Willett, the 2016 Masters Champion, is the leading Englishman after following his six-under 66 on Friday with a 70, which has four birdies on the back nine.
Matt Wallace hit six birdies in a 70 to get four, while fellow countryman Matt Fitzpatrick had a dou ble bogey on the last to score a 74.