Group One-winning sprinter Eagle Falls had to be euthanased on Thursday after breaking a leg during trackwork at trainer David Hayes' Euroa property.

The 2011 Oakleigh Plate winner earned more than $1 million during his 37-start career which included eight wins and spanned three countries.

Hayes said the seven-year-old sprinter wasn't galloping hard at the time but smashed a sesamoid bone and had to be euthanased.

"It's a sad day," Hayes said.

"He was a terrific old horse. He won an Oakleigh Plate and was probably unlucky not to win another one."

Eagle Falls was also Group One placed in the 2010 Newmarket Handicap and Manikato Stakes.

In between he embarked on an international campaign finishing fifth in both the Group One Golden Shaheen in Dubai and the Group One Krisflyer International Sprint in Singapore.