The United States dominated the Presidents Cup foursomes today, winning four of the five afternoon matches to forge three points clear of the Internationals going into the penultimate day.
The holders lead by 9-1/2 points to 6-1/2, having won seven of the 10 matches played on the second day at Fancourt's Links course in South Africa.
Fred Funk and David Toms drew first blood, beating Australians Robert Allenby and Stephen Leaney 4 and 3, before Kenny Perry and Jerry Kelly survived a nervy finish to edge out South Korea's K.J. Choi and Australia's Peter Lonard 2 and 1.
Choi and Lonard had dropped shots at the second, third and fourth before Perry and Presidents Cup rookie Kelly tightened their grip, reeling off three successive birdies from the par-five ninth.
But the Americans then faltered in strengthening winds, bogeying the treacherous par-four 12th and losing out to six-foot birdie putts by Choi on 15 and 16 before a matching bogey at the 17th was good enough to secure the win.
U.S. Open champion Jim Furyk and Justin Leonard then completed a 5 and 4 victory over Vijay Singh and Mike Weir, Furyk having put them five up by chipping in from just off the edge of the green at the par-four 12th.
Tiger Woods and Charles Howell III also survived a poor finish to seal a one-hole victory over South Africans Tim Clark and Retief Goosen.
The Americans had been four ahead with five to play, but their lead was eroded as their opponents birdied 14 and 16, where world number one Woods missed a four-foot putt for a half. Ernie Els and Australia's Adam Scott provided the only consolation for the Internationals in the alternate shot format, Els chipping in for birdie from greenside rough at the last to secure a one-hole victory over Chris DiMarco and Phil Mickelson.
The Internationals had led by a point following yesterday's opening foursomes but the US drew level on 5-1/2 points by winning three of the five fourball matches on this morning.
Six fourball matches follow tomorrow before the trophy is decided over the closing 12 singles matches on Sunday.