The Gold Cup favourite is now 3/1 from 4/1 for the race with Ladbrokes following on from the victory. His closest rival in the betting is Native River at 5/1.
The eight-year-old trained by Pat Kelly went off as favourite in the Grade 2 John Mulhern Galmoy Hurdle and saw off the challenge of Bapaume who came second.
He makes a winning return after his success in the RSA Chase last March at the Cheltenham festival.
Nicola Mcgeady of Ladbrokes said: "Presenting Percy has cemented his position as Gold Cup favourite after winning the Galmoy today. Before the race we didn't see any money for him for Cheltenham, but now that we know he's fit and well, we are expecting support to increase."
To win the 2019 Gold Cup
Presenting Percy - 3/1
Native River - 5/1
Kemboy - 6/1
Clan Des Obeaux - 7/1