AP photo by Darron Cummings / Jon Rahm watches his chip shot onto the 18th green during the third round of the PGA Tour's Memorial Tournament on Saturday at Muirfield Village Golf Club in Dublin, Ohio.

DUBLIN, Ohio — Jon Rahm showed again why he's one of the most explosive players in golf, and this time he made sure he demonstrated that dynamic nature with his clubs.

His back nine at Muirfield Village Golf Club on Saturday afternoon capped what he considers one of the top rounds of his career, a 4-under-par 68 that turned Rahm's four-shot deficit into a four-shot lead entering the final round of the Memorial Tournament. It also put the 25-year-old Spaniard on the verge of reaching No. 1 in the World Golf Ranking.

"Today could be one of the best rounds of golf I've played in my life," Rahm said, a tribute to a course getting so close to the edge it drew comparisons with those set up for a major championship. "And it's hard to believe how passively it came, compared to how I played usually."

His passion is so great it can hurt as much as it helps. On this day, facing this test, Rahm kept his cool. He watched Tony Finau reach the par-5 11th hole in two for a sure birdie that would leave Rahm four shots behind.

There was no panic. Rahm said he told his caddie on the 13th tee: "If we can finish the last six holes under par, it's a great finish. And whatever we have to do to make a comeback, we'll make a comeback."

Birdie. Birdie. Birdie. Birdie.

Two double bogeys by Finau and bogeys by Ryan Palmer on two of his last three holes helped Rahm reach the four-shot advantage over those two.

A victory would allow him to join Seve Ballesteros as the only Spaniards to reach No. 1, provided that Rory McIlroy — the four-time major champion from Northern Ireland whose eighth stretch on top started in early February — doesn't finish as a runner-up. McIlroy shot a 72, which wasn't a bad number on a day when the average score was 73.7 but still left him 10 shots back.

Said Rahm: "I've got to get out there tomorrow, play solid again and get the job done, and think about the No. 1 afterwards."

The former Arizona State star was at 12-under 204 as he goes for his fourth PGA Tour victory and 10th worldwide.

Finau and Palmer were two shots ahead of fourth-place Danny Willett (70), the 2016 Masters champion with just two victories since that surprising green jacket.

All three Baylor School graduates who are PGA Tour regulars were close together on the leaderboard, with Harris English (74) and Luke List (79) tied for 29th at 1 over, a shot ahead of Keith Mitchell (73), who had a share of 37th.

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AP photo by Darron Cummings / Jon Rahm tees off on the 18th hole at Muirfield Village Golf Club during the third round of the Memorial Tournament on Saturday in Dublin, Ohio.

Finau avoided bogeys on the front nine, poured in a 50-foot birdie putt and then easily reached the green on the par-5 11th for a two-putt birdie to reach 12 under.

One swing changed everything.

Finau's tee shot on the par-3 12th in a swirling wind sailed 15 yards over the green, leaving a downhill chip from thick rough to a green that was yellow and ran toward the water. He left it short, chipped through the green and made a double bogey. Finau took another double bogey on the 17th hole with an awkward lie in the rough.

"It was good, and then it wasn't good," Finau said. "Man, this golf course can get you in a heartbeat. You just try and put your best foot forward every hole, every shot, and try and play as well as you can. The greens are firm. There's enough wind up there to think about. They're fast. A little disappointed in my finish, but look, I'm in a good position going into tomorrow.

"And it's going to be tough tomorrow."

Muirfield Village is rebuilding all the greens starting Monday, and tournament officials are not afraid to let the course go to the very edge for the strongest field of the year.

It wasn't easy to get shots close. It wasn't easy to hole putts. It wasn't easy to do anything.

It was the highest average score for the third round at the tournament hosted by 18-time major champ Jack Nicklaus since 2012, when Tiger Woods earned the most recent of his five Memorial victories. There won't be a sixth this year. Woods said he felt better and he played better, posting a 71 — but he still was 14 shots behind.

That's what made Rahm's round so special. The ball kept rolling on the greens, and he realized it was happening to everybody. He dropped only one shot, on the par-3 eighth. And his finish was simply sublime.

Rahm played in the group in front of Finau and saw him reach the 11th green in two. His only concern was hitting the green at No. 12, trying to pick up a birdie or two, and if he had to rally on Sunday, so be it.

He hammered his tee shot 360 yards over the bunker that set up a wedge shot to 12 feet from the hole for birdie on the 13th. He wisely laid up on the 14th, with the tees moved forward to play at 322 yards, and hit wedge to put the ball five feet away for birdie.

Right of the green on the par-5 15th in two shots, with the green running fast and away from him, he hit a flop-and-run to three feet for a third straight birdie. And then he capped it off with a 25-foot birdie putt on the 16th.

Just like that, he had the lead and was in control.

Rahm has had a mathematical chance to reach No. 1 ever since the PGA Tour resumed six weeks ago. He missed the cut in the return tournament, though, and finished out of the top 25 in the other three events he had played before the Memorial.

Now it's right there in front of him — along with a course that won't be getting any easier.

"Whatever happens tomorrow happens, but it'll be a great test for me to learn for the future, for major championships," Rahm said. "Because this is going to be the closest thing we get to a major championship without being one."