Sizing John faces a high-class field of 11 rivals in the Leopardstown Christmas Chase this afternoon.

Jessica Harrington 's seven-year-old is on the cusp of going 12 months unbeaten and created history by winning Gold Cups at Leopardstown, Cheltenham and Punchestown.

He made his seasonal debut at Punchestown on December 10 and soundly defeated Djakadam in the John Durkan.

Harrington said: "I've been happy with Sizing John since the John Durkan and this seems a nice spot for him, the n we can see what we do after that - I'm just taking each race as it comes.

"There are 12 runners, so it will be fierce competitive, but I think the bigger field might actually help him. We've just got to keep out of trouble.

"The ground looks like being lovely so that will be more in our favour."

Djakadam takes him on again but his stablemate Yorkhill might arguably pose the biggest danger to Sizing John as he steps up in trip to three miles.

Yorkhill has not been seen since he threw away certain victory when he hung violently left in the Ryanair Gold Cup at Fairyhouse in April.

"It's a very big ask for Yorkhill on his first start of the season," said Patrick Mullins, assistant to his father, Willie.

"Sizing John put up a huge performance in Punchestown. I thought that was probably his best ever performance and he's going to be very hard to beat.

"Yorkhill seems in good form and because he has to go left-handed, that cuts down our options considerably in Ireland.

"It's his first run over three miles since his point-to-point days, but his pedigree is all staying and we're hoping this will be a stepping stone to the Gold Cup.

"We'll have a lot better idea where we stand after."

Of Djakadam, Patrick Mullins added: "I don't think he ran up to his best the last day. He didn't really carry Paul (Townend) the whole way.

"We're just hoping that run has blown the cobwebs away and that he'll travel with a bit more enthusiasm.

"I'll be disappointed if he doesn't improve on that run and, on his Punchestown Gold Cup run, he should be capable of giving Sizing John a race." Minella Rocco stayed on powerfully to finish second to Sizing John in the Cheltenham Gold Cup and takes his chance for Jonjo O'Neill.

He has, though, never come close before, or since, to matching that level of performance, including when he was pulled up at Cheltenham in November.

O'Neill said: "He was very disappointing at Cheltenham but the ground probably didn't help and he seems in good form.

"Obviously, long term the Gold Cup is the plan but he will have to show more in Ireland. We are looking forward to a better run."

Minella Rocco's owner JP McManus is also represented by the veteran Carlingford Lough and Edwulf who collapsed close home in the four-miler at Cheltenham on his last start in March.

There are five runners for Gigginstown House Stud, headed by Noel Meade's Road To Respect who took advantage of Yorkhill's waywardness at Fairyhouse.

Last time out he lost out narrowly to Outlander in the JNwine.com Chase at Down Royal and the pair meet again. Alpha Des Obeaux Balko Des Flos and the returning Valseur Lido who looked sure to win the corresponding race 12 months ago before fading late on, also represent Gigginstown.

Andy Lynch 's Zabana completes the field.