The Republic of Ireland defender is away on international duty with O'Niell's side, who have a friendly match in Turkey on Friday, but he has been explaining how his game has come on over the past two years with the Seagulls and the national side.
Duffy says his consistent form is down to believing in himself and regular football under both Hughton with Brighton and O'Neill with Ireland.
He said: "Chris has given me the chance to play in the Premier League where I'm developing and Martin has given me the chance to play on the big stages and in a big tournament.
"You take little things out of each one of them and it's all coming together a bit now and hopefully there's more to come. I'm still a bit raw in some things I do but I'm getting better.
"It's weird. I'm still quite new. I've been here for two years but it's not that long. How it's changed in those two years is mad.
"To be part of the older ones, or the more experienced ones, is a bit weird but I know most of the lads from playing with them growing up.
"It's probably easier now than it was two years ago when I didn't know them. I feel very comfortable."