Mark Todd, two-time Olympic gold medallist from New Zealand, was the first competitor to ride into the venue, doing eventing individual dressage with his horse Gandalf.

"I really could not have hoped to have done anything better than that at this stage of career. I am delighted with it," Todd told journalists after completing his round of action.

Todd, 52, who was voted Rider of the 20th Century by the International Equestrian Federation, won the individual three-day event at the Los Angeles Games in 1984 and again in Seoul in 1988.

His return for his sixth Olympics after eight years' retirement strengthens the chances of the five-man New Zealand squad in the medal race.

"It's a little bit hard getting myself to the back and gear. Honestly, being here doesn't feel like being away at all. Eight years slipped by very quickly."

On his horse Gandalf, Todd said "I was really pleased with him. It's only a short time since I got the horse and it can't be any better."

On the weather here, he said "It's been very, very hot and I'm absolutely drenched. I suppose seven minutes in the sauna wasn't that bad."

More than 200 athletes from 42 countries and regions will compete for six team and individual gold medals in the 11-day events.

Nicholas Touzaint, 28, and his horse Galan de SauVagere will lead defending champion France. Touzaint was No. 3 in the latest individual eventing rankings compiled by the International Equestrian Federation (FEI) and two-times winner of European championship. The horse and rider also won at Badminton in May, thus giving France quite some strength. Jeane Teulere trailed with an individual rank of 65.

But it is far from a sure Olympic team gold for the French squad.

The British team is still one of the hopefuls even after the withdrawal of Princess Zara Philips due to horse injury. William Fox-Pitt, 39, and Mary King, 47, are both world-class riders. Fox-Pitt is currently world No. 1, while King is No. 3.

The British team won an incredible total of 21 European championships but had never laid their hands on the Olympic eventing team gold since after the 1972 Olympics. They will be no less craving for the honor than any others.

The United States team, which took bronze at Athens 2004, claimed the title at the 2007 Pan American Games. Philip Dutton, winner of the 2008 Kentucky title, was on two gold medal-winning teams for Australia and now joins the U.S. team following a nationality change. Amy Tryon was third at the 2006 World Equestrian Games and returns with Olympic horse POGGIO II.

The German team holds the World Championship title and wants to set the record straight after it lost in Athens 2004, where one rider crossed the start line twice. Frank Ostcholt, No. 10 in the world rankings, won the 2007 test event in Hong Kong.

Australia has 9th ranked Megan Jones and 18th-ranked Sonja Johnson, while Sweden, Canada, Brazil, Italy and Ireland will also be sending teams to compete.