Rory McIlroy knows he will have to play with the patience and intelligence of a chess grandmaster if he's to claim his fifth major win and his second US Open at Pebble Beach.

But he also knows a fast start will put leader Gary Woodland under pressure after a workmanlike 70 left him alone in sixth place, five strokes behind the man from Topeka on six-under par.

The conundrum is that the capricious, cliffside venue on the spectacular Monterey Peninsula is not a course where you can freewheel and so he needs a ruthlessly efficient final round if he's to be a factor down the stretch.

"I'm still in with a shot," McIlroy said after a two-putt birdie at the 18th allowed him to break par for the third day running. "I definitely think I can shoot 65 or 66 on this golf course. That's probably what it is going to take tomorrow. Everything has got to be on. 

"You've got to get off to a fast start, you've got to play the par fives well and you need to hit it in the fairways all day. It's difficult. It is possible, but it is difficult. 

"I'm going to have to go out there and play the way I've played. I've hit the ball in the fairway for the most part, I've been smart, I've hit to the right part of the greens. Today I felt like I didn't get as much out the round as I could have, but at the same time, at a US Open, you have to hang around."

Woodland will be entering uncharted territory as the 54-hole leader in a major after he shot a two-under 69 to lead by a stroke on 11-under par from 2013 champion Justin Rose, who shot a 68

An added problem for McIlroy is that defending champion Brooks Koepka is lurking just four shots adrift in a tie for third with Chez Reavie and South African Louis Oosthuizen after a 68 as he chases a third successive US Open win and a fifth major victory in his last nine starts.

Another seven players are within seven shots of the leader, including 2010 champion Graeme McDowell, who eagled the 18th to shoot 70 and cling to the fringes of contention on four-under.

The fact that Woodland has won just three times on the PGA Tour and failed to convert any of his seven, 54-hole leads into wins can only give the rest hope.

"Shane Lowry played with him the first two days and came in yesterday and said what a golfer this guy is," McDowell said. "Said he putted incredibly well Thursday and Friday and maybe [the question was] was he going to be able to maintain that level of putting.

"But obviously it's a lonely place out there, and this golf course, it's a little bit of a sleeping giant. And it doesn't take but a few loose shots before you can be in scramble mode out there."

McIlroy had his worst putting round of the week on moving day and while he knows he needs to convert more of the chances he creates, he cannot throw caution to the wind.

He said: "It's definitely not a golf course or a golf tournament where you can go chasing. So even though I'm still a few off the lead, it's a wonderful opportunity for me to go out there and try to add to my major tally.

"I've been very pleased with how I've played all week. I felt for the most part today I did the right things. And I need to do 18 more holes of that, but just get a little bit more out of the round tomorrow than I did today. 

"I'm expecting the conditions to be similar, but I could see the course just getting a little firmer and a little faster and just being a touch trickier."

The challenge for the entire field is that Pebble Beach is like a giant chessboard and every shot is a conundrum.

With the first seven holes offering several excellent birdie chances, the chasers need to get into the red early before the gruelling test from the eighth to the 13th.

"Yes, I'd love to play those holes in a few under and get myself right in the thick of things, but I can't put myself under pressure to do that because you've just got to let it happen," McIlroy said.

"The greens are so small, and when it gets a little firm like this and they start to tuck pins in little corners, it's angles, it's all angles. You're trying to think and move ahead. 

"It's a little bit like chess where you're crossing paths, going from the third green to the fourth tee and seeing a group tee off 17 and watching their balls land on the right side and kicking in. You have to anticipate what your ball is going to do along the ground, as well.

"It just takes a little bit of concentration because there's some shots where you need to land the ball ten yards short of the pin and some holes, like back into the wind, it might only be three or four yards.

"But you can't go firing at pins because you're going to one-hop it over the back all day. It's playing to the front edge of the greens. Hitting the right trajectory, so the ball does what you think it's going to do when it hits the ground, basically."

McDowell's title challenge was on life-support before he revived it by making a 35 footer for a closing eagle three.

Still, he knows he needs something extra special if Woodland and Rose hold firm.

"That was fun in the last, but I'm not kidding myself," he said. "I'm not in this tournament yet. So it requires strong seven holes to open up tomorrow to try and give myself something to hang on to coming in."

Like McIlroy, Koepka needs to see some putts fall so he can go into the back nine with a chance.

"I don't need to go out and chase," Koepka said after a bogey-free round. "I don't need to do much. Just kind of let it come to you."

Rose has struggled from tee to green but he's been magical with the putter and like McIlroy, he's also expecting a chess-like challenge.

"One back gives me the freedom to feel like I've got everything to gain, nothing to lose," Rose said after taking just 23 putts a 68. "I'm not chasing, really, I'm so close to Gary that I have to go out and play my game tomorrow." 

Woodland has no plans to back off but it remains to be seen if his sometimes suspect putting will hold up under pressure.

"I know if I play my game and play like the way I've been playing, the guys from behind me are going to have to do something really, really special," he said. "So I'm going to go out, stay within myself, stick to my game plan and try to extend that lead more than anything."

When asked if he'd had putts for the US Open as a kid, he said revealingly: "No, I didn't. I don't know if I spent any time on a putting green when I was a kid, I was too busy hitting driver."

Tiger Woods, clearly not 100 per cent physically, appears to be too far back on level par to challenge while Shane Lowry needs his putter to heat up if he's to turn a good week into an excellent one

After a 70 left him tied 33rd on one-over, Lowry said: "It was nice to go out there and throw another sub-par round at it. Hopefully, I can go out and get into red figures for the tournament tomorrow and see where that leaves me.

"I think if I go out and shoot three or four under tomorrow, I will have quite a good finish this week. I am driving the ball, hitting some nice iron shots and the putter is behaving. So it's all been good. 

"I just need to keep riding that good form for a while, keep going into tomorrow. I have a nice two weeks off and then keep it going into Lahinch and keep it going after that."

Lowry has emerged from the doldrums this year to become one of the favourites to make Pádraig Harrington's European team at Whistling Straits in 2020.

It's the number one goal for the Clara man over the next 18 months, and he's convinced that McDowell can win back his place in the team after his resurgence in form over the past four months.

"It hasn't been easy for Graeme over the last while, and we are obviously very good friends. I am around him quite a lot, and I can definitely say that G-Mac has his swagger back. There's no question.

"We've seen it this year and again this week, and it's great to see because we're both off the boil for a while and it's not an easy place to be.

"He is rolling the ball well on the greens, and that's big for him. He has his confidence and his strut back. And he's one of the ballsiest golfers I have ever know, so it's really good to see him back after a couple of average years.

"I can definitely see him contending for the Ryder Cup team again after missing out on the last two.

"Rory will definitely be there for sure, and hopefully I can keep this run of form going for a long time to come and make it too because making that team is a huge goal of mine."

Whether or not McIlroy adds another major to his resumé this summer, Lowry still considers him the game's number one player when he's firing on all cylinders.

"He's just one of the best in the world, isn't he? He drives the ball so good. If anything, this course doesn't suit him. If we were playing a different US Open course, he'd be very hard to beat because he drives the ball so well and he's putting alright these days

"I always say, when Rory has got his A game, he's virtually impossible to beat."

Danny Willett’s 67 left him alongside McDowell and when asked his view on Pebble Beach, he said:
"It doesn't really favour anybody in particular. At the end of this week, you're going to get the best golfer winning, which is the way it should be."