But they hold the bragging rights after knocking United out of the Scottish Cup the last time the two sides met and are keen to hold on to them.
Wide man Tiffoney said: “The mood’s positive because we know in the derby games that form goes out the window.
“It's two teams going at it and we fancy ourselves for the win.
“These are the games we look forward to and we know what a win would do for us, it would be massive.
“Any win in the derby is massive and we know if we win this game then it kicks us on for the rest of the season.
“We all know what it means to people in Dundee. The two clubs are right beside each other, every Dundee fan knows a Dundee United fan so we know what it means.
“It’s actually a good game to play in, I think a lot of people enjoy watching a Dundee derby.” Dundee's recent slide down the Premiership table doesn't make good viewing for anybody at Dens Park, but Tiffoney is confident they can dig themselves out of relegation danger.
He said: "Obviously we're not relaxed about the situation, but we know that we can ...