“City just dont let you get the ball back. Its so difficult and you get frustrated but theyre such quality players.
“Liverpool will maybe let you have the ball a bit more but they press you and counter-attack on you so quick.
Albion sit 15th in the table, with five points from seven games, this season but have already played City, Liverpool, Manchester United and Tottenham.
They remain three points clear of the bottom three and on the Seagulls start, Duffy said: “Youve got to play everyone, so its okay.
“Wed maybe like a few more points on the board but I think the performances have been better than what the points show.
Pep Guardiola has revealed that Sergio Aguero has been playing through the pain barrier and is a fitness doubt for Manchester Citys trip to Liverpool next weekend.
The Argentina international injured his foot in the Citizens 2-1 win over Newcastle United at the start of the month.
Aguero has been used in four of Citys five matches since then, but he has only lasted around an hour in each of those games before being taken off.
Speaking ahead of his sides trips to Hoffenheim and Liverpool over the next seven days, Guardiola told reporters: “Sergio is struggling a bit with some problems in his foot.
“He is not 100%. He has not recovered from what happened against Newcastle and we spoke about playing 60 minutes and we were lucky he scored at the right moment.”
Agueros goal in the 2-0 win against Brighton & Hove Albion on Saturday made it five in seven league outings this term.