After a rain delay of nearly one hour, play began in very soft conditions and little breeze although later in the day the breeze did pick up for the afternoon players, although to no great extent.
The scoring however told the story of a golf course which was vulnerable under attack from the world's best and that 52 players are under par at the completion of 36 holes reflects a much more benign golf course than would have been the case without the rain.
McIlroy felt things were not as good as yesterday but he was philosophical about it all in his post round media conference.
"Yeah, another very solid day's work," said the leader. "Conditions were obviously a little tougher than they were yesterday and especially on our front nine which is the back nine, you needed to stay really patient, because the rain was coming down pretty heavily at times.
"It was just about managing your game and putting the ball in the fairway and trying to put it somewhere on the green and I was able to make a few birdies on the back nine and to finish off with that eagle on the last was nice.
"Pretty scrappy, to be honest, around the start of the front nine. But a couple of key up and downs which were pretty important but really happy with the day's work and another great chance to win a major championship going into the weekend."
McIlroy has developed into a very good front runner in recent times and was asked about that aspect of his game.
"I think I've had to learn to be a good frontrunner. I may be wasn't quite comfortable in that position at the start of my career, or like sort of 2009, 2010, 2011; especially 2011, the Masters, I was four ahead and I wasn't quite comfortable in that position.
"It's taken me a couple of years to grow into that where I am comfortable, and, you know, my mind set has stayed the same since that day at Augusta. If I'm two ahead going into the weekend here, I'm going to try to get three ahead; and if I'm three ahead, I'm going to try to get four ahead; and if I'm four ahead, I'm going to try to get five ahead. I'm just going to try to keep the pedal down and get as many ahead as possible. That is my mind set whenever I'm leading the golf tournament."
Day who came into the event under an injury cloud of sorts raced through his opening nine in a brilliant 30 and, although he dropped a shot at the 15th, birdies at his final two holes got him within one.
Day acknowledged he had a break with the weather but was delighted the way he played.
"I think we got a little lucky on the draw, teeing off in the afternoon today. "We didn't get as much rain. We didn't really get a delay out there which was nice. The guys in the morning, I've just seen some pictures of some of the guys in the morning. It was pouring pretty hard.
"But hey, I played great. I got off to a great start today. That's obviously the last thing that I expected to shoot 30 on the front nine. But you know, I put some good shots together out there today to give myself the opportunities out there to really take advantage of the front nine. Obviously the back nine is just a little tougher."
"It was a little surprising," added Day referring to his apparent turnaround in form and health. "Obviously I wasn't expecting it. Just with the poor form that I've had over the last, you know, few tournaments that I've played.
"But we worked very, very hard last week before I had the vertigo, and then after when I came in Monday, Monday through Wednesday, did phenomenal preparation. I busted my butt out there and worked very, very hard.
"I'm excited. You can't not be excited to be in or around the lead in a major championship. Obviously they are the hardest tournaments to win. It's going to be a lot of fun.
"I've been close a lot of times. I've said it before; I just have to keep knocking on the door and hopefully it will fall my way one day. It's either hopefully it falls my way or just knock the door down and take it."
Furyk continues his marvelous season but realises this is not necessarily a golf course that suits his style of game.
"The design of the golf course is severe, and I think what I've done really well to this point is be real patient and I've really picked and chosen the spots where I could be aggressive. I've taken advantage of some short irons in my hand and made some putts. I think that's why I'm sitting in the position I'm in.
"Conditions will have to be soft again tomorrow. I can't imagine the course drys up that quick. I will have the same mindset, instead of feeling like I can fire at pins, I'm going to pick and choose those spots and pay as patient as I can."
Former PGA Tour of Australasia event winner, Ryan Palmer shares 4th place with the ever present Rickie Fowler and Finnish golfer Mikko Ilonen.
An eagle at the last kept Phil Mickelson within striking distance, his round of 67 has him at 6 under par and within three of the lead.
Matt Jones if the next best of the Australians after Day at 3 under and in a share of 17th while Adam Scott and Geoff Ogilvy are not yet out of it at 2 under and 26th and Marc Leishman staged a brilliant last burst with a birdie, eagle finish to be in the weekend field at even par.