The Bees overturned a 1-0 deficit to claim a 3-2 aggregate win over the Swans.
And Frank thinks the loss fired up his players for their promotion push.
"We now have an experience that we can use that could be extremely beneficial," Frank said. "It could be the thing that helps us in the final.
"It's all about, when you play a final or a decisive game, focus on your job or your task as a player. Focus on what you can do something about and not all the other bits, that's what we've talked a lot about."