|-12 J Rahm (Spa); -8 T Finau (US), R Palmer (US); -6 D Willett (Eng)|
|Selected: -5 J Day (Aus), H Norlander (Swe); -4 M Wallace (Eng); -2 R McIlroy (NI), J Spieth (US); -1 M Fitzpatrick (Eng); +2 T Woods (US)|
Spain’s Jon Rahm will take over as world number one if he can convert his four-shot lead into victory in Sunday’s final round at the Memorial Tournament.
Rahm holed four birdies in succession from the 13th as he hit a four-under 68 to lead on 12 under from Americans Ryan Palmer and Tony Finau, who had 73s.
England’s Danny Willett is fourth on six under after a 70 in Ohio.
World number one Rory McIlroy stayed at two under after a 72, while Tiger Woods had a 71 to improve to two over par.
The 15-time major champion, who complained of a bad back before Friday’s second round, said he was “moving better” on Saturday.
“That’s the way it is these days, I felt like I did the first day,” added 44-year-old Woods, who has won the Jack Nicklaus-hosted tournament at Muirfield Village a record five times.
For McIlroy, it was a day of one shot gained, one given back. On five occasions he birdied a hole, only to bogey the next.
Finau fades as Rahm races clear
Joint overnight leader Finau holed a 50-foot birdie putt on the 11th and rolled in another on the 12th to move four clear of Rahm on 12 under par.
However, the American double bogeyed the par-three 12th after an errant tee shot into rough. Rahm, playing in the group ahead, birdied the 13th and the lead was down to one.
The 25-year-old then holed birdie putts on the next three holes as 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 on the 17th following another errant drive.
Rahm, who closed with two pars to record the joint lowest score of round three, will take over as world number one if he wins on Sunday and McIlroy does not finish joint second. He can also take top spot if he finishes second, McIlroy is outside the top 30 and Justin Thomas does not win.
He would become only the second Spaniard to top the rankings, after Seve Ballesteros.
“I’ve got to reflect on a good job,” he said.
“The plan is to do the same again, fairways and greens and if I can hit the ball on the green to 30 feet I fancy my chances.”
Palmer, who led overnight with Finau, dropped two shots in the final three holes to drop back level with his fellow American.
Willett, the 2016 Masters champion, is the leading Englishman after following his six-under 66 on Friday with a 70, which featured four birdies on the back nine.
Matt Wallace hit six birdies in a 70 to get to four under, while fellow Englishman Matt Fitzpatrick had a double bogey on the last to card a 74.