SAN FRANCISCO — Tiger Woods and Steve Stricker were perfect as Presidents Cup partners, and they got enough help from everyone else Saturday to put the Americans in position to stay perfect on home soil.

With an improbable rally by Woods in the morning and pure putting by Stricker in the afternoon, they became the first partnership in the Presidents Cup — and the first in 30 years of any team competition — to go 4-0.

Phil Mickelson had a chance to join them with an undefeated record using different partners. Mickelson and Sean O'Hair, who won their match handily in the morning, each had a birdie putt inside 15 feet on the final hole for the win, but had to settle for a halve.

With only 12 singles matches remaining Sunday, a 12½-9½ deficit looks daunting for the International team.

No team has rallied from three points behind on the final day to win the cup outright, and the Americans have lost only one singles session in the seven previous Presidents Cup matches.

"Last time we had a five-point mountain to climb in Montreal, and it looks like we will have something to climb," Geoff Ogilvy said after collecting his first point of the week in teaming with fellow Australian Robert Allenby.

Woods and Stricker are the first partners to go 4-0 in any team competition since Larry Nelson and Lanny Wadkins won all their matches in the 1979 Ryder Cup at The Greenbrier.

The perfect mark looked unlikely in the morning foursomes, when the International team was poised to catch the Americans by leading the final three matches on the course.

Woods and Stricker, who had missed four putts inside 8 feet during a six-hole stretch in the middle of the match, were on the verge of being closed out on the 17th hole. The International team was 1 up, with Mike Weir facing 5 feet for birdie. Woods tried to drive the green and found the bunker, and Stricker hit a poor shot to 25 feet.

Miss it, and Weir could win the match by making his short birdie putt.

Woods watched his birdie putt tumble into the cup on the final roll. Weir pushed his birdie putt, and the match was all square heading to the par-5 18th. From the fairway, Woods drilled a 3-iron and twirled the club in his hand. The ball landed softly on the green and stopped 8 feet away. Tim Clark blasted his bunker shot long, and the International team conceded the birdie and an unlikely 1-up victory.