Kauto Star and Ruby Walsh© Photo Healy Racing
Ruby Walsh identified the 2006-07 jumps season as being Kauto Star's reign of invincibility.
The star jockey steered the legendary chaser to 17 of his 19 victories in Britain and Ireland, including two Cheltenham Gold Cups and five King Georges for trainer Paul Nicholls.
But it was his exploits during an unbeaten 2006-07 term, which reached its zenith with Gold Cup glory at Cheltenham, that Walsh remembers especially fondly.
He said: "That was the year he was at his best. I always thought that was a phenomenal season.
"That year he had speed and he had stamina.
"I thought in the 2006-07 season he was near unbeatable."
Kauto Star, who was put down after suffering pelvic and neck injuries in a fall in a paddock, looked as though his best days were behind him after he was pulled up in the 2011 Punchestown Gold Cup.
But he famously roared back later that year to win a fourth Betfair Chase at Haydock and his fifth King George at Kempton.
Walsh told the Morning Line: "I was happy Paul took his time and decided not to retire him.
"He was very happy with him and he lifted the roof off at Kempton.
"But there were so many great days with him, you'd hate to single out one.
"He definitely lit up a lot of seasons for me - h e was just such a good racehorse.
"Kauto Star was brilliant. You just would have loved him to have enjoyed his retirement a bit longer."
