Katherine Copeland and Sophie Hosking won the women's lightweight double sculls to claim Britain's fourth rowing gold medal of the London Olympics.
The duo, who only teamed up this season, were the fastest qualifiers for the final and continued their fine form to beat China by two seconds.
World champions Greece led through the first 500m but could only finish third as Copeland and Hosking rowed clear.
"I can't believe this is real and we just won," Copeland told BBC Sport.
"I've been trying all week not to think about it because it has been making me cry."
Copeland and Hosking became the third female British boat to win a gold medal at the London 2012 rowing regatta. Before this event, no British woman had won an Olympic title.
It was also Great Britain's 10th gold medal of the Games, with rowing's tally now at four gold medals, two silver and three bronze.
Copeland, who almost quit rowing two years ago because she wanted to remain based in the north east, only joined forces with Hosking at the start of the 2012 World Cup series.
They gave a slight indication of their potential with a bronze in Belgrade, although they finished outside the medals in regattas in Lucerne and Munich.
In the final, they started quickly but Greece opened up a slight advantage in the opening quarter of the race at Eton Dorney, with China going through the mark in second.
Britain moved up to second by halfway and then put in a devastating burst to sprint away from the field and win in seven minutes 9.30 seconds, with the fast-finishing China pipping Greece on the line.