Europe's challenge at Whistling Straits came unstuck on Sunday as Darren Clarke, Brian Davis, Luke Donald and Padraig Harrington all struggled. Ireland's Harrington endured the worst round, carding a six-over 78 to fall back to one over.
English duo Davis and Donald stumbled down the stretch to slide back to four under and two under respectively.
While Darren Clarke, the first-round leader, saw his challenge fade with three straight bogeys from the 15th.