Striker Lee Novak rescued Town with a late goal, their first in 359 minutes of football, and after losing four of their previous five matches Grayson's side limped into the play-offs as Scunthorpe hit the woodwork three times.
Grayson said: "It doesn't matter what happens before, it's what you do in the play-offs themselves that counts.
"I've been involved in teams that have finished third, fourth, fifth and sixth as a player and a manager with different outcomes.
"There's no right or wrong way to get there and once there it's a lottery. Ultimately it's how you end up that matters."
Grayson added: "It's been a long season for them physically and mentally and the unbeaten run probably took a lot out of them mentally. They reached the play-off final last year and didn't get too much time off in the summer. We need to get a bit of spark back."