NICOLA Wilson and Opposition Buzz gave Great Britain's eventing team a flying start to Greenwich’s Olympic cross-country test today.

The combination are regarded among the world's leading cross-country exponents, and they lived up to that billing in front of an estimated 50,000 crowd at Greenwich Park.

The world and European team gold medallists delivered a brilliant round, finishing almost 12 seconds inside the time allowed of 10 minutes, three seconds.

It was just the launch-pad Britain wanted, having started cross-country in bronze medal position.

An elated Wilson, who was called into the Olympic team after Piggy French's horse DHI Topper W suffered an injury last month, remained on her dressage score of 51.70 penalties.

Fans ran over to congratulate her after she finished the course, some waving union flags. She pumped her hand in the air and waved.

"He was just unreal, what a fantastic horse," Wilson said. "This is his favourite stage by far. When he gets to cross-country day it's like all his birthdays and Christmases have come at once. He never fails to give me the wow factor."

Australian Christopher Burton commanded the initial headlines, going clear inside the time by a remarkable 17 seconds.

Burton, who won the World Equestrian Festival eventing title at Aachen in Germany earlier this month breezed around the 5,728-metre course on HP Leilani.

And it strengthened Australia's position in the team competition after they held the silver medal place overnight.