Padraig Harrington has made a barnstorming start to the Nissan Open in Los Angeles, leading an illustrious field by three shots after an opening eight-under par round of 63.

Harrington, winner of last year's European Tour order of merit, carded 10 birdies three of which came in his opening three holes.

The Dubliner, who has not won on US soil since the Barclays Classic in 2005, is being chased hard by Phil Mickelson and Briny Baird both of whom are three shots further back on five under.

World number two Jim Furyk is a further shot behind while Vijah Singh sits on his shoulder on three under.

Paul McGinley, the only other Irish golfer in the field, is among the later starters and was level par through two holes of his opening round.