Although the bookies are certain to put the home side - who finished fourth in League One last season but lost to Sheffield Wednesday in the play-off semi-final - down as the favourites, Allen is keen for his side not to be complacent.
He said: "It's a tough start, it's never easy to play a team that has been promoted in your first game.
"It doesnt get much easier after that either as we face two tough away tasks in Chesterfield and at Port Vale."
Allen also feels that Brentford's start will be important to his teams progress this season.
He added: "Last season we had an average start but were largely inconsistent, we'll be taking a game at a time but everybody will be looking to get points on the board as quickly as possible."