Rory McIlroy's first-round score of 66 at the 150th Open was only good enough for second place but it was a supporter who paid the price after the world number two's wayward tee shot struck his hand and broke it.

Four-times major winner McIlroy was two shots behind American Cameron Young after round one, with one mis-hit shot sending Charlie Kane - who also handles social media for the PGA Tour - to St Andrews Community Hospital for treatment.

"Fractured hand after Rory McIlroy's drive landed on my knuckle. He shouted fore. I did not heed the warning," Kane tweeted.

Kane posted images of a purple welt on his hand where the ball had struck him, showing a swollen middle finger.

But despite the rap on the knuckles, he was all smiles when he returned to the course with his arm in a sling.

McIlroy is looking to win the Claret Jug for a second time after his triumph in 2014.