World numbers three and four Luke Donald and Lee Westwood have a lot to do to get anything out of their foursome match against Keegan Bradley and Phil Mickelson after the opening nine holes at Medinah.

Bradley and Mickelson have been the flagship American pairing so far in the competition and they got off to a lightning start by birdieing one and two for an early 2-up advantage.

Holes three, four and five were halved before America again won two on the bounce as Westwood and Donald first bogeyed the sixth before Mickelson found the green with his second on the par-five seventh and Bradley put his eagle putt close enough for a concession.

The eighth was halved in birdie threes before Bradley went off-line from the tee on the par-four ninth. However, Mickelson's wedge was on fire and he sent his approach inside the ball of Westwood, who had an easier fairway position.

Donald's birdie try was low of the hole but Bradley made no mistake to move the lead to 5 up.