He's been runner-up in his national open - the only one of golf's four majors he has failed to win - a record six times and, last year, his reputation took a huge hit at the tournament when he deliberately hit a still-moving putt in protest at the set-up of host venue Shinnecock Hills. 

This year's championship takes place at Pebble Beach, a course where he has won five times - most recently, in February of this year - and where his grandfather used to caddie. 

• USGA responds to talk of players boycotting US Open

With his 49th birthday falling on Sunday, many (including top commentator Jim Nantz) have predicted this will be the year Mickelson finally gets his hands on the trophy he covets most and become just the sixth player to complete the career grand slam.

• A Rory US Open win would be "catastrophic" for bookies

• Jason Day brands himself an "underachiever"

However, for that to happen, he can't afford any more costly mistakes like he made in the opening round.

Sitting at level-par for the tournament, Mickelson had a 22-inch putt for par on the third hole, his 12th. 

No problem for a seasoned pro like Phil? Not so fast.

Watch what happened...

Oh Phil...