Great Britain and Ireland's amateurs defied expectations to grab a 7-5 lead over the United States on the first day of the Walker Cup at Royal Aberdeen.
Northern Ireland's Paul Cutler was the outstanding performer, winning both his matches, as the home side eclipsed their illustrious opponents on a day when fortune fluctuated with the same regularity as the elements.
Conditions veered from perfect to atrocious as an afternoon storm swept across this spectacular links. GB&I also dodged a scrape with the rules on the way to their unexpected advantage.
Although they won three of the four morning foursomes, Nigel Edwards' team were fortunate to take their lead into the afternoon session after it emerged Jack Senior had used a caddie who is a professional golfer.
By employing the services of his pro brother Joe, Senior had breached the official conditions of competition. Had the error been discovered during the match he and Andy Sullivan would have been penalised up to two holes.
But the breach was not confirmed by the authorities until their 2&1 victory over Russell Henley and Kelly Kraft had been completed. It was deemed the error had not been "knowingly" made and therefore the result could stand.
"We had asked the R&A if it was OK for Joe to caddie and were told it was, but clearly it's not," Edwards said. "It was a mistake, it wasn't intended."
American captain Jim Holtgrieve made no protest and was more concerned that his early starters in the singles made inroads into the deficit. Peter Uihlein duly obliged with a spirited victory over Tom Lewis, who struggled throughout.
Senior found it hard to cope with the trauma of his morning caddie controversy and was never ahead in his defeat by Jordan Speith and when Harris English came from four down after seven to beat Andy Sullivan the Americans had turned a 3-1 deficit into a 4-3 lead.
Then came the middle order surge from Edwards' team, led by the youngest player in either side. Showing remarkable resolve, 17-year-old Rhys Pugh came from three down after eight to beat Patrick Rodgers even though the American had birdied his first five holes and added another by chipping in at the seventh.
James Byrne, who like Pugh had sat out the morning session, closed out Nathan Smith at the 17th and Steven Brown secured victory at the last after Russell Henley three-putted the penultimate green.
Cutler, who had starred in a 5&4 foursomes victory, maintained his fine form with a 2&1 win over US amateur champion Kraft to ensure the lead going into the final day.
America needed their top player Patrick Cantlay to make sure the deficit was only two points and he duly obliged with a composed 2&1 win over Michael Stewart in the final singles.