The rival north east clubs are currently embroiled in a relegation battle and are separated by just one point in the league table.
The Magpies are currently placed 19th, while the Black Cats sit just outside of the relegation zone with one point more than their arch rivals.
Sunday's game at St. James Park will also be Rafa Benitez's first home game in charge of the Magpies and Clark believes it will be a monumental clash.
"This is the biggest derby of all time because of the money that's riding on staying in the Premier League next season because of the television funds," Clark, who is currently managing Scottish club Kilmarnock, told Sky Sports News HQ.
"If one team loses, it looks as though that team could potentially go down. Hopefully Rafa Benitez has enough time to get his methods across."