Champion Chase hero Moscow Flyer is to begin another winter campaign at Navan on Sunday.

The 11-year-old is on course for the two-mile Fortria Chase, having won the Grade Two contest for the past two seasons.

"It's all systems go for his comeback on Sunday and he's been working away well," trainer Jessica Harrington told the Racing Post.

"He went to Punchestown and jumped four fences for Barry Geraghty recently and he's also been to the Curragh working on grass a couple of times.

"Barry (Geraghty) is coming down here on Thursday to pop him over a fence again and then it's on to Navan."

Moscow Flyer is currently the highest-rated chaser in Britain, having won 26 races and more than €1 million in prize money.

He is already as short as 5-4 favourite to win the Queen Mother Champion Chase for a third time at Cheltenham in March.

A possible opponent on Sunday is Rathgar Beau, who ruined Moscow Flyer's 100 per cent record in completed outings over fences when beating him by a short head in the Kerrygold Champion Chase at Punchestown in April.

"He's ready to go but I haven't made up my mind whether he'll run at Navan or wait for the Clonmel Oil Chase the following Thursday," said trainer Dusty Sheehy.

"It all depends on the ground and a few other factors, but if it was looking like coming up very testing at Clonmel then two-and-a-half miles may be a bit further than he'd like for his first start back.

"If that were the case we'd probably run over the two miles at Navan on Sunday."

Rathgar Beau unseated his rider at the final fence in the Fortria Chase 12 months ago when in second place, and looking held, behind Moscow Flyer.

Willie Mullins is monitoring the weather before deciding on his team for the Open meeting at Cheltenham. Mullins has entries in the Paddy Power Gold Cup Chase on Saturday and in the Greatwood Handicap Hurdle and the Independent Newspaper Novices' Chase on Sunday.