The home side took the lead after only six minutes through on loan striker Kyle Lafferty. The Burnley frontman fired in an angled drive following a pass from Joseph Kendrick.
Mansfield found life difficult in the opening stages of the game, although they did have a chance in the 10th minute when Adam Birchall raced through only to fire wide of Kasper Schmeichel's goal.
The game settled down and Darlington's early fluency was lost as the visitors came back into the game.
In the 34th minute Simon Brown cut inside before wasting his chance with a 15-yard drive that was easily stopped by Schmeichel.
Just before half-time a mistake from Clark Keltie let in Stephen Dawson, but Schmeichel raced out of his goal to bravely save at the feet of the Mansfield player.
Darlington scored again with an early second half goal. Akpo Sodje capitalised on a defensive mix-up to fire in at the far post giving Jason Whyte no chance.
Two minutes later Dawson almost pulled a goal back but he was denied by an excellent tip over by Schmeichel.
Darlington increased their lead in the 57th minute when Sodje headed on from a Carlos Logan corner and captain Matt Clarke fired in from close range.
The game's final goal came in the 64th minute when Logan chipped the ball into the area and Dutch defender Shelton Martis headed in his first goal in English football.