Golf-United States on brink of winning Presidents Cup

* Spieth disqualified for picking up moving ball

* U.S. closing in on seventh straight title (Updates with first four-ball matches)

By Steve Keating

JERSEY CITY, New Jersey, Sept 30 (Reuters) - The International team's hopes at the Presidents Cup were hanging by a thread as Patrick Reed and Jordan Spieth overcame a mid-round rules blunder to claim the first four-ball point on Saturday and add to a commanding United States lead.

The 2&1 victory over Australian Jason Day and South African Louis Oosthuizen stretched the U.S. advantage to 12 1/2 to 2 1/2 over the hapless Internationals at Liberty National.

The biennial competition was in danger of being decided for the first time on a Saturday, which would render Sunday's singles matches redundant.

Needing a sweep of all four four-ball contests, the United States were in a position to do just that after Daniel Berger and Justin Thomas took down Venezuela's Jhonattan Vegas and Japan's Hideki Matsuyama 3&2.

The Americans were also leading the two remaining matches.

Reed and Spieth, who have partnered each other in every session, overcame a 12th hole miscue that appeared to open the door for the Internationals.

Spieth was disqualified from completing the 12th and denied an opportunity to match Day's birdie putt when Oosthuizen's eagle attempt scooted past the cup and the British Open champion scooped up the ball before it had stopped.

The error allowed the Internationals to grab a 1-up lead but in the end it proved only a minor setback as Spieth and Reed rallied with three straight birdies from the 15th to steal the point.

The United States have won nine of 11 Presidents Cups, including the last six from the International team, comprised of players from the rest of the world except Europe. (Editing by Andrew Both)