Despite Walsh getting the better of Long Run in both the Betfair Chase at Haydock and the King George at Kempton on Kauto Star this season, he feels the younger horse still has plenty going for him.
Long Run won both the King George and Gold Cup last season but Kauto Star, now 12, has gained his revenge.
“Kauto is not getting any younger and Long Run beat us comprehensively in the Gold Cup last year,” said Walsh. “It’s over three and a quarter miles, and on a different track and a different day.
“He was only a length and a half behind at Kempton so he closed the gap from Haydock.
“Would I get off Kauto Star? No. Do I think Long Run should be favourite? Yes.
“I’m looking forward to it and I hope we all get there.”
Walsh, meanwhile, hopes Mikael d’Haguenet can return to the form he showed as a novice hurdler after he won his second race of the season at Punchestown on Saturday.
Walsh said: “He’s getting back to what he was. That race yesterday only had four runners but the Shark’s (John Hanlon) horse (Western Leader) went a serious gallop and never stopped.
“Mikael took it off him turning in and idled a bit but I liked the way he picked up from the last.
“He’s getting back to where he was, he’s going in the right direction.
“He was an incredible horse as a novice hurdler and I hope he can come back to that.”