Furyk and Snedeker birdied the opener and were 2 up after five thanks to another under-par score, with McIlroy and McDowell consistently making pars.
The Americans were the first to bogey at the par three eighth and yet another par for the Northern Irish duo meant that the deficit was cut to one.
More pars continued for McIlroy and McDowell and they fell victim to an American birdie on the 11th to again fall 2 down.
After 15 consecutive pars world number one McIlroy finally found the cup with a birdie putt at 16 to cut the score to 1 down before his birdie putt at 17 missed by a whisker.
That meant the match headed down the 18th with Furyk and Snedeker guaranteed at least a half-point.
McIlroy's drive pierced the middle of the fairway but Snedeker couldn't follow suit, pushing his tee shot into a bunker down the right.
Furyk found a solid approach from the sand to the front of the green and that left it to McDowell to fire in a close second.
The 2010 US Open champion could not deliver though and the hole was halved to move America 8-4 ahead going into the afternoon fourballs.