Webb Simpson wields a red-hot putter in another crushing Ryder Cup win with Bubba Watson

Watson was a virtual bystander as Simpson drained a remarkable range of birdie chances, making five in six holes around the turn to put the match beyond Europe's reach.

The US Open champion found the centre of the cup to give his team the lead at the third, and he then matched Molinari's birdie at the long fifth.

Watson then contributed with a delicate pitch and putt for a winning birdie at the seventh, and Simpson birdied the next two to cancel out Rose's two at the eighth and Molinari's three at nine.

Simpson continued his hot streak on the greens to win the 10th, and his fourth straight birdie at 11 was bravely matched by Molinari, who appeared to exchange angry words with the galleries on his way to the next tee.

Simpson had the air of a man who could not miss on the greens as he poured in another 15-footer for birdie at 13, his seventh of the round.

Watson's immense length off the tee enabled him to easily reach the 609-yard 14th in two blows, and Rose could not match the Masters champion's cast-iron birdie to leave the home duo celebrating their second point.

"Webb just was a little anxious, wanted to make all the putts," said Watson afterwards. "I did the par-fives and he did the rest, and that's pretty much all we did."

The home side will take a commanding four-point lead into Sunday's singles, but Watson was not taking victory for granted.

"The team is not going to lay down. Europe is not going to lay down. They are not going to give it to us. We have to play good golf and come out focused and ready to win some points," he said.