Phil Mickelson has insisted that he takes confidence from his US Open record ahead of this year's tournament at Chambers Bay.

The American has finished runner-up at the US Open on a record six occasions, but he claims that falling short so many times does not have a negative impact on his approach as he continues his bid to become just the sixth player to complete a career Grand Slam.

"I've always been somebody, ever since I was a kid, that got motivated by failure, that worked harder because of failure," Mickelson told reporters.

"Some people get discouraged by that and it almost pushes them away. But for me it's been a motivator to continue to work harder and get over that hump, whether it was trying to win my first Major championship, that took significantly longer than I thought it would, whether it's trying to win an Open Championship, or whether it's trying to win a US Open championship.

"The fact that I've come so close is actually a motivator for me to work harder, and it's encouraging that I've done well in this tournament. It's encouraging that I've had success and that I've played some of my best golf in this event and that I've had a number of opportunities."

Mickelson will play alongside Bubba Watson and Angel Cabrera in the first two rounds.