RORY McIlroy didn't wait for the crowd to finish crossing, letting fly with a long iron right over the heads of practise day spectators at Oakmont.

THIS week's US Open at Oakmont might be one of the most anticipated of recent times and crowds at the Pittsburgh course have turned out in force, even for the practice rounds.

Plenty were keen to get a look at Rory McIlroy and as he made his way around the course there was no shortage of spectators accompanying him.

As filmed by this fan in a grandstand behind one of the tees, though, Rory wasn't bothered by their presence.

As several people make their way across the fairway in the distance, McIlroy tees up and unleashes with a long iron.

There's no reaction from the crowd on the fairway so it can only be assumed the ball comfortable flew over them and landed somewhere further on.

Still, McIlroy was obviously not happy with the effort as he immediately calls for another ball from caddie JP Fitzgerald and is teeing up a second go as the video comes to an end.

Four-time major winner or not, launching golf balls over people's heads takes some confidence so we can at least be sure McIlroy is happy with the state with his ball striking.

That will be key this week as the rough lining Oakmont's fairways and greens is already proving a talking point and Jordan Spieth suggesting finding fairways might be the most important statistic for the week.

McIlroy will attempt to win his second US Open this week after taking the title at a wet and soft Congressional Country Club in 2011.

US OPEN PROS SHOCKED AT FIRST SIGHT OF OAKMONT:

[VIDEO:4937989148001]

Want video tips delivered straight to your inbox? Subscribe to iseekgolf.com newsletters.