Rory McIlroy insists he will remain aggressive in his bid to win a maiden major title despite opening a commanding lead over the field at the US Open.

Following up his superlative 65 on Thursday, McIlroy produced a 66 on Friday to stand at 11-under-par at the halfway stage - some eight shots clear of his nearest rival when he finished.

It could and should have been even better for the 22-year-old but for a double-bogey at his last hole, the 18th, when he found water.

That slip brought to an end a run of 35 holes without a dropped shot and saw him slide back towards the field from 13-under.

Speaking of the costly second shot at 18 which resulted in the double, he told Sky Sports: "I just got a bit of grass between the club face and the ball and it just turned over a little bit.

"I was trying to play it out towards the front-right of the green and unfortunately it went into the water and I ended up making double.

"I would have been great to get that ball up and down for bogey because bogeys are also very important at this tournament.

"But I can't really dwell on that, I played 35 very, very good golf holes over the first two days and that's what I've got to focus on."

Indeed, McIlroy - who fired five birdies and an eagle at eight when he holed his second shot - claims he achieved the objective he set himself at the start of the second day.

"To be honest that was my goal at the start of the day, to get into double digits," he continued.

"But when I did that at eight I had to reassess! So I said 'right, let's see if I can get to 12' and I got to 13. Obviously with what happened at the last it's back to 11.

"But it's been a great couple days and I just need to keep it going."

The Northern Irishman squandered a four-shot lead heading into the final round of The Masters just a couple of months ago, but insists he will look to maintain his attacking style as he bids to close out victory at Congressional.

"I still have to be aggressive and go for my targets like I have over the first couple of days, but really par golf from here in could be good enough," he added.

"I've got to go out there and play the way I have been playing, be aggressive to the targets I pick and make very committed swings.

"I feel comfortable with my game, I feel comfortable on this golf course and I'm giving myself plenty of opportunities and taking a few of them. So I've just tried to keep it very simple."