Simenon recorded his first victory over timber since May 2012 with success in the Kevin McManus Bookmakers Grimes Hurdle at Tipperary.
One of the most admirable dual-purpose horses in training, the dual Royal Ascot hero has been campaigned exclusively on the Flat in recent times, finishing second in last season's Gold Cup at the Royal meeting and fourth in the Melbourne Cup.
He has also run in Japan, Hong Kong and Dubai.
Settled in mid-division through the early stages of his jumping return by Paul Townend as Little King Robin cut out the pace, the Willie Mullins-trained seven-year-old was still full of running three out and soon joined issue with Darwins Fox from the second-last.
The pair took the final flight almost as one, but Simenon proved the stronger on the run to the line, winning by a length and a quarter as the 10-11 favourite.
Townend said: "His jumping over the first couple was deadly and when I needed at the last he produced.
"It was a true gallop from start to finish, he has loads of class and it's nice to win that.
"I knew the other horse stayed very well but it's nice to get him back to winning ways - he's a real flag-bearer for the yard."