The two sides are scheduled to meet in Fife this afternoon.
A 2-1 defeat in the reverse fixture in December was enough to force Dundee off the top of the SPFL Championship and it is a result which would prove hard to get over, not least as it put a dampener on the squad's festive plans.
Having since recovered their position as league leaders, Letheren is adamant Dundee are not willing to suffer further disappointment this afternoon. "They came here and fully deserved the win last time," said the goalkeeper. "We owe them one after that as they spoilt our Christmas night out in Belfast. It put a real downer on our festive do, so we are definitely due them one."
The Dens Park side have enjoyed two wins since Paul Hartley took over as manager and Letheren has taken to the methods of the former Alloa Athletic coach. However, he is also quite aware that Cowdenbeath will be in good spirits thanks to manager Jimmy Nicholl.
"I was at Kilmarnock with Jimmy for two years and he is a great character," said the Welshman. "Jimmy is one of the funniest guys I have ever come across in football. He has got Cowdenbeath playing well and getting results."