Melbourne - Justin Thomas again proved a rock with his third point of the Presidents Cup Saturday, but his team-mates failed to match the exploits as Tiger Woods' Americans slipped further behind.
The world number four, an 11-time winner on the PGA Tour, was teamed with Woods on the opening two days, but with the playing-captain resting for the Saturday morning fourballs, he partnered Rickie Fowler.
Thomas was the anchor, draining winners on the second, eighth, 11th and 16th at Royal Melbourne to help beat Australian Marc Leishman and Chinese rookie Li Haotong 3 and 2.
But it was their only win, with Ernie Els' Internationals clinching two matches with the other tied as they target a first victory in the match-play event since 1998.
It put them in the box seat with a commanding 9-5 lead heading into four foursome -- or alternate shot - matches on Saturday afternoon, ahead of 12 singles on Sunday.
With 30 points at stake, the first to 15.5 will win the cup.
"I'd much rather be 0-3 and us be winning by five or six points," said Thomas. "You know, everyone that goes out there, we just have to go out there and try to do our job."
Sensational Mexican Abraham Ancer matched Thomas with a third point for his team, including a wonder putt on the third.
Paired with impressive South Korean Im Sung-jae, just 21 but who has risen to the occasion, they outplayed Patrick Cantlay, who dropped one of those crucial putts on Friday, and Xander Schauffele.
Bogeys from both Americans on the eighth handed Ancer and Im a 1-up advantage and they never looked back in a convincing 3 and 2 win.
"These are the moments that we've been practising for our whole life, and to be able to do that, it's a lot of fun," said Ancer.
"But my partner was incredible. I think we both played some really good golf today."
Woods kept faith with Webb Simpson and Patrick Reed, who were trounced by Leishman and Ancer on Friday, but they struggled again against Hideki Matsuyama and Taiwan's CT Pan, whose iron play was laser-like.
They lost the opening two holes and with Matsuyama and Pan's putters running hot, including an eagle on the sixth for debutant Pan, the US never recovered, crushed 5 and 3 in the biggest margin so far.
Veteran Adam Scott's experience came into play in his match alongside South Korea's An Byeong-hun against Matt Kuchar and Tony Finau.
They went one down at the fifth but Scott nailed a long birdie putt on the eighth to even it up and another at the 11th for the lead before Finau held his nerve at the 18th to sink a birdie to split the match.
Results from the Presidents Cup Saturday at Royal Melbourne Golf Club (par 71). International team first:
Match score: International team 9 United States team 5
Internationals 2.5 United States 1.5
Marc Leishman/Li Haotong lost to Justin Thomas/Rickie Fowler 3 and 2
Im Sung-jae/Abraham Ancer beat Xander Schauffele/Patrick Cantlay 3 and 2
Hideki Matsuyama/CT Pan beat Webb Simpson/Patrick Reed 5 and 3
Adam Scott/An Byeong-hun tied with Matt Kuchar/Tony Finau
Draw for Saturday afternoon's Presidents Cup fourth-round foursome matches between the International and USA teams at the Royal Melbourne Golf Club (International team first):
All times SA
Louis Oosthuizen/Adam Scott v Dustin Johnson/Gary Woodland - 04:32
Marc Leishman/Abraham Ancer v Justin Thomas/Rickie Fowler - 04:43
Cameron Smith/Im Sung-jae v Xander Schauffele/Patrick Cantlay - 04:54
An Byeong-hun/Joaquin Niemann v Matt Kuchar/Tony Finau- 05:05
International: Li Haotong, Adam Hadwin, Hideki Matsuyama, CT Pan
US: Tiger Woods, Bryson DeChambeau, Webb Simpson, Patrick Reed