Nicky Henderson is worried the handicapper could potentially scupper the Crabbie's Grand National target of Triolo D'Alene after his 49-length victory in Kempton's williamhill.com Chase under Jeremiah McGrath.

Henderson's runner has suffered breathing and knee problems since winning the Hennessy Gold Cup in 2013, and was having his first run since finishing third at Sandown in a class two handicap last January.

Yet he relished this comeback and jumped flawlessly in the three-runner contest on ground that would not have played to his strengths.

The nine-year-old made most of the running and looked to have the race won in any event when Ptit Zig (2-5 favourite) blundered at the penultimate fence, unseating Sam Twiston-Davies. Wishfull Thinking was allowed to come home in his own time under Richard Johnson to take second.

Henderson said: "We have had to wait a bit. He was always a very good horse - he won a Topham (at Aintree) and a Hennessy Gold Cup. We have a little plan, but I've probably gone and scuppered it.

"The Grand National was the plan last year. He ran a good race one day at Sandown and we thought he was on the right road, and then an hour later at the stables, he was lame. We had to put screws in knees and everything, and we had to start all over again."

Breathing problems have also been an issue for the Sandy Orr-owned gelding.

Henderson said: "His lack of racecourse action is all to do with his breathing. There is no more to be done about his wind. He has had all the procedures you can do and there was nothing more you could do.

"In this ground you are always going to amplify wind problems. To be honest, he has been very good at home. We have not been hearing the noises, but earlier this year he sounded like a steam train."

He added: "His jumping was great and he has been round Aintree and Newbury, so we know he can jump. Jerry got him into a lovely rhythm. I had him in the novice hurdle, but with three runners, I felt I owed it to keep him in this race. I just hope the handicapper does not over-react."

McGrath is looking forward to the National, for which Triolo D'Alene is 25-1 (from 33s) with Paddy Power.

He said: "It is well documented he hasn't got the best breathing in the world, but when he gets into a rhythm like that he can just jump from fence to fence and he's saving ground all the time.

"He totally surprised us. To be fair, he has done plenty of work at home, because he was supposed to run at Doncaster three weeks ago.

"But his breathing was clean as a whistle. He handled this ground - it worried everyone else - but he has feet like dinner plates. And he'll improve for better ground, that's the other side of it.

"The ground will be safe at Aintree - that's the plan now, anyway."