Irish keep up the pressure
Meanwhile, Masters champion Phil Mickelson lost out on a golden opportunity to put pressure on the leaders.
Clarke twice visited sand on the way to dropping two strokes at the 11th (his 2nd) but held his head well to get back to his original seven under with birdies at the 14th and 16th before he cracked a glorious long iron to fifteen feet behind the flag at the clifftop 17th and rolled in the putt for a third successive gain.