Phil Mickelson has said that he will need to be lucky if he is to win his first British Open title at Muirfield next week.

The American, who finished tied for second in 2011, admitted that he has not been at his best when in pursuit of the Claret Jug, but believes that now he is ready to challenge for the honour.

"I have really not played my best golf in this event but it's time to play now, shoot the scores and hit the shots I've spent 20 years trying to work on," the 43-year-old told reporters.

"I think the last eight or nine years I've started to play better golf, but it's still a challenge for me.

"I'm always cautiously optimistic. The British Open is one of my favourite events because it's one of the most challenging events for me, but one of the things I've learnt over the years and especially here at Muirfield is you need an element of luck."

Mickelson has won three Masters titles (2004, 2006, 2010) and one PGA Championship (2005).