Duff has to give weight all round in his bid to land back-to-back victories in the Vodafone Ireland Foundation Supports Gaisce Ballycorus Stakes at Leopardstown on Sunday.
Edward Lynam's front-running stalwart has to give between 5lb and 18lb to his five rivals as he is burdened with a Group Two penalty for a victory at Doncaster in September.
However, the seven-year-old is reported in top form following his first run of the season on this track three weeks ago.
Duff set the pace but faded into fourth place behind Famous Name over a mile.
The outing is said to have done him the world of good and he now reverts to his optimum trip of seven furlongs this time. His jockey Fran Berry expects him to put up a good show.
'He won the race last year but has a Group Two penalty this year which means he has 10st. That will make it harder for him,' said Berry.
'He ran well on his reappearance and he would have needed the race badly. He will strip fitter on Sunday and back to seven furlongs will suit him better.
'The ground is forecast to be good to firm and that will suit him ideally.'
The County Meath trainer is also expecting a big run.
'He had a prep run there a few weeks ago and that should put him right. This has been the early-season plan, then he'll go back to Doncaster again later on,' Lynam told At The Races.
'He goes from start to finish. It's goodbye starter, hello judge with him. He's a warrior, a very brave horse.'
King Jock almost snatched the Amethyst Stakes from Famous Name as he pulled four and three-quarter lengths clear of Duff that day.
His trainer Tracey Collins hopes the nine-year-old's liking for the course will stand him in good stead.
'He's come out of his last race really good and I'm glad to see the size of the field has whittled down a little bit," said the Curragh trainer.
'He's in very good form. He loves Leopardstown and hopefully he's going to run a big race for us.'
