Goals by Caolan Boyd-Munce – his first for the club – and Donnell McNeilly put Wycombe into the fourth round for the first time since the 2006-07 season.
“I think we’ve had some really good pockets of play. I think we look a threat and pretty solid, so it’s just trying to get more and more details into them,” Duff said.
“We’ve tweaked a couple of things but there’s some good players in there, and they’ve obviously been well coached as well, so it’s just trying to add a little bit to that rather than rip it up and start again.”
Wycombe reached the League One play-offs by finishing fifth last season – having been in the automatic promotion places for much of the campaign – but were beaten by Charlton Athletic.
And after a poor start to the season under Dodds, which left them in 19th place, Duff has stressed the need to “keep working, keep working, keep working”.
He added: “That’s four halves we’ve won. I keep saying, ‘Win the next half, win the next half,’ because even if you’re 4-0 down, you can still come in at half-time, reset and win the second half 1-0 and try and take a positive out of it.
“Don’t worry about where you want to get to, just win the next half and then pop your head up after 10, 15 halves and think, ‘Oh, we’re doing alright,’ or ‘We need to adjust things.’ That’s the way I work – just chunk it down constantly.”