Europe are no strangers to recovering from a seemingly insurmountable position, though, having bounced back from a 10-6 deficit after two days at Medinah in 2012 to win the second of three trophies on the spin.
If Clarke's men are to make it four in a row on US soil this evening then a huge effort is required, which the skipper believes is more than possible.
"We're going to have to work hard," he told BBC Sport. "It's been done before from a worse position. We need to believe in ourselves. There is a precedent."
Rory McIlroy looked to lead the European charge on Saturday when helping to draw the scores level, but the Northern Irishman was left unhappy when on the receiving end of some verbal abuse from certain members of the vociferous crowd.
"Someone just said a few derogatory things I thought were over the line," McIlroy said. "I tried to get him removed. It fuelled me a lot. The more they shouted, the better we played, so I hope they shout at us all day tomorrow."
The United States have won the Ryder Cup on just two occasions in the past 23 years.