Brighton, who finished sixth in the Premier League last season to secure qualification for the Europa League, face AEK Athens in their Group B opener on Thursday.

They'll enter the match as favourites, but can't afford to be complacent against their first opponent or any other, says the manager.  

"We cannot forget where we started and who we were. We can't lose our DNA," he told reporters.

"If we think that we are better than we are, then we make a big mistake. If we want to become bigger than this competition, then we still have to compete at this level first.

"We have studied AEK a lot. They are a good team, very aggressive with and without the ball. It will be a very tough game."

Brighton face a difficult task in their bid to progress past the group stage, where they will also come up against former champions Ajax Amsterdam and three-time finalists Olympique de Marseille.

"Our group is one of the stronger groups but for us, it is better. If we want to win in this moment we have to compete against the best teams," De Zerbi said.

The English side are fresh off the back of an impressive 3-1 Premier League win at Manchester United, but the Italian urged his team to wipe the result from their minds, adding: "The challenge of this year is to forget the game we play the day before and to focus only on the next game.

"To keep the result and the good emotion but to forget other things. The game in Manchester is finished. We have to think only about the next game."