Open Championship leader Rory McIlroy will take to the Royal Liverpool links later looking to avoid the dreaded second-round syndrome which has dogged him all year.

The Northern Irishman produced some blistering iron play in shooting a six-under-par 66 to lead the 143rd Open by one stroke from Italian Matteo Manassero.

However, the two-time major winner knows he will have to combat a trend which has seen him regularly shoot over par in his second round.

In the current calendar year he is 50 under par for his first round and nine over for his second.

He was first-round leader of the Open once before at St Andrews in 2010 with a 63 - the lowest first-round score in the tournament's long history - but bad weather the following day saw him shoot 80.

McIlroy benefited from benign morning conditions on Thursday but tees off at 2.27pm today in what is expected to be changeable weather.

"When you go back out on Friday after a good score you know what you can do, so you're going out with some expectations compared to Thursday," he said.

"I think I've just got to approach it trying to hit solid shots the first few holes and play my way into the round, just like I did (on Thursday).

"I just have to take it one hole at a time, one shot at a time - I know everyone says it and you've heard it a million times, but it's true.

"I feel I'm well prepared this week for whatever the conditions," he added.

"I've practised in windy conditions the last few weeks. I've practised the shots that I might need for a bad day like Friday might be.

"Will that help in any way? It might do, because you're really just concentrating on one shot at a time when the weather is like that.

"It's not like I've shot good scores in first rounds and haven't backed them up before. I'm used to doing that. I just haven't done it recently."

Seven players begin the day in a share of third place on four under, including Italian brothers Francesco and Edoardo Molinari, world number one Adam Scott and Sergio Garcia.

Scott, who squandered a four-shot lead with four holes to play at Lytham in 2012, was delighted to keep McIlroy in his sights.

"It's important, you've got to keep pace with a guy like Rory," Scott said.

"He has the potential to really put his foot down. I've seen him shoot lots of low rounds and there's nothing stopping him from doing that either.

"I don't want him running away (with it). We've seen what happens, he wins majors by eight shots (in the 2011 US Open and 2012 US PGA).

"And Martin Kaymer did it just a few weeks ago in the US Open and it makes for a tough weekend when you're that far behind having to force it."

Defending champion Phil Mickelson, who has not won since his victory at Muirfield 12 months ago nor shot under par in a major since, carded a two-over 74.