The Ospreys have won in their last five previous appearances at Principality Stadium in all tournaments and their last nine against the Blues in the Guinness PRO12.
And Tandy is expecting his players to react well to the big occasion.
He said: "Judgement Day is growing year on year and becoming one of the game's great spectacles.
"This is a great opportunity for them to showcase themselves on a big occasion. They are young kids but they are not afraid to express themselves and they just want to be part of things.
"It has been a disappointing season for us so far but it is not over and there is nothing like the passion of a derby game in front of a big crowd to get players going."
Last year's record crowd of 52,000 looks set to be broken after the WRU announced ticket sales had surpassed 62,000 at the start of the week.
A crowd of around 70,000 is now expected at Principality Stadium in the Welsh capital on Saturday.
Mark Davies, the chief executive of Professional Rugby Wales, the umbrella organisation of the regions, was delighted to see fans growing support for the event.
"What the ticket sales show is the great enthusiasm and engagement there is for the game in Wales," he told The Guardian.
"Our relationship with the WRU is now excellent and Saturday is an excellent example of how we are working for our mutual benefit.
"We have the interest in Wales, as the ticket sales for this weekend show, and regional rugby is on the up."
To buy tickets for the GUINNESS PRO12 Grand Final click here. Also follow us on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the GUINNESS PRO12.
63x46.png){kind=logo}