Second-placed Rovers travel to Griffin Park to take on the third-placed Bees in a final-day shoot-out for automatic promotion this weekend.
With two points separating the teams, a draw will see Flynn's men join Bournemouth in the Championship next season.
But Doncaster are just a point behind the table-topping Cherries and Flynn has still not given up hope of clinching the title.
"We will play to win against Brentford on Saturday. All of our focus is on winning the game," he said.
"I don't believe in playing for a draw. If it happens then so be it, but we will be looking to win.
"If we can win our game and Bournemouth don't win then we can still win the league, and that has to be the aim."
He added: "At the start of the season I think most people would have taken going into the last game of the season with a chance to get promoted.
"Every footballer wants to play in games like this. It doesn't get better than a promotion match in front of a full house. It's going to be very exciting.
"It's down to us and them and whoever is best on the day will deserve to win it. We have to make sure that is us."