Helen Glover and Heather Stanning confirmed their status as gold medal favourites as they stormed into the final of the women's pair in the rowing in a new Olympic record time.
Roared on by a packed crowd at Eton Dorney, Glover and Stanning won the opening heat of the Olympic regatta in a time of six minutes and 57.29 seconds, beating the previous best by over four seconds.
Glover and Stanning controlled the race from the outset, leading the field by a half a length at the 500 metre time-check before pulling smoothly clear to beat the United States crew by a length.
Great Britain's men's eight finished second in their heat behind three-time world champions Germany and will have to go through a repechage on Monday to reach Wednesday's final .
Earlier, the British women's quad of Melanie Wilson, Debbie Flood, Frances Houghton and Beth Rodford finished a disappointing fourth in their heat and must now negotiate a repechage to reach the final.
The British men's lightweight four of Peter Chambers, Richard Chambers, Rob Williams and Chris Bartley produced a barnstorming finish to beat world champions Australia and reach the semi-finals.
The men's pair of George Nash and Will Satch were also victorious in their heat - but their achievement was overshadowed by Hamish Murray and Eric Bond smashing the world's best time in the other heat.
Murray and Bond won in six minutes, 08.50 seconds - almost six seconds better than the previous best, set by Matthew Pinsent and James Cracknell at the 2002 world championships in Seville, Spain.
Britain's men's double of Bill Lucas and Sam Townsend were edged into second place by New Zealand in a tight race but it was enough to qualify for the semi-finals. The quad of Stephen Rowbotham, Tom Solesbury, Charles Cousins and Matt Wells were a length behind world silver medallists Germany but they did enough to make the semi-finals.
Alan Campbell rounded off Britain's interest in the opening day of the regatta by comfortably winning his heat from China's Liang Zhang to reach the quarter-finals in a packed field.