Rory McIlroy storms into the lead with 63 in Memorial Tournament

Rory McIlroy continued his impressive form by earning a three-shot lead on the first day of the Memorial Tournament.

The Northern Irishman, who recorded victory in last week's BMW PGA Championship, finished the day on nine-under-par thanks to some thrilling golf in front of the Ohio crowd.

Despite appearing to be struggling with a knee problem throughout the day, McIlroy started the round strongly by reaching four-under on his front nine.

A double bogey on the 14th hole proved to make little difference as he eagled both par-fives to climb to the top of the leaderboard.

American duo Bubba Watson and Chris Kirk are tied for second place alongside Paul Casey, with Keegan Bradley, JB Holmes and Michael Thompson a shot further back.