overshadowed the Olympic individual three-day event yesterday.

The Bermudian rider was distraught after her mare suffered a broken leg in a fall at the second fence and the horse was later put down (see story on page one).

American David O'Connor, beaten by Tumbridge and Bermuda's Gold at the Pan Am Games in Winnipeg last year, rode a perfect cross-country round yesterday to lead the Olympics individual three-day event, but two of his fellow riders were taken to hospital after falls.

O'Connor remained on his overnight score of 29.00 penalties after the cross-country leg, and leads Heidi Antikatzidis of Greece by 8.40 points into Friday's final show jumping test.

New Zealand's Mark Todd moved into third place on 39.00 when German Marina Koehncke, second in dressage, was eliminated when her horse refused to enter the water after missing a jump.

Australia's Andrew Hoy, who won gold in the team event, was 0.80 penalty points behind in fourth place.

In total, 13 of the 38 entries either retired from the course or were eliminated. Among those to withdraw was New Zealander Blyth Tait, the reigning Olympic and world champion.

A number of other horses were taken to the clinic after their falls.

Riders continued to fall through the afternoon but there were no further serious injuries to riders or horses.

Experienced performers such as Todd and O'Connor attributed the high attrition rate to the lower quality of riders in the individual event compared with the team event.

"Many countries put their better riders in the team, and maybe some lesser riders in the individual, and so you're always going to get more trouble,'' Todd said.

O'Connor called his ride fantastic and said Custom Made has done a great job so far, but then he offered some hope to those trailing him ahead of today's final round.

"There's no question that show jumping is his weakest phase, but that's just one of those things,'' the American said.

"He gets aggressive going at fences and that's when he starts to add the rails,'' he said. O'Connor could knock down one rail on Friday or exceed the time limit by eight seconds and still win the event.

Seven of the first 12 riders of the day suffered falls, the most serious putting Brazilian Roberto Macedo in hospital with a fractured pelvis. He suffered no internal injuries and did not need surgery.

Danish rider Nils Haagensen fractured his shoulder when he fell off his mount Discovery II.

MJ Tumbridge: riding Bermuda's Gold in Tuesday's dressage.

Another one down: Uruguay's Henry Gramajo and his horse Potencial fall at the Darug Bulada jump yesterday.