Rangers will be huge underdogs.
But Hungarian midfielder Buzsaky, 25, said: "It's a game we can't lose, so we're going there to relax and to try to play good football.
"The Championship and Premier League are different but if you can play well in the Championship you can play anywhere in the world.
"Sometimes the standard is even better than the Premier League.
"So there is nothing to fear - we'll be trying to win the game."