The Dens Park youngsters came from behind to edge a fiercely competitive derby at Station Park, Forfar, tonight.
Dundee threatened first through Max Anderson fired over from a good position.
And only a fine save by United keeper Fraser Currid prevented the Dark Blues going in front after 26 minutes.
Almost immediately, Currid’s opposite number Sam Johnston denied Cammy Murray the opener.
However, it was only delayed temporarily, Murray drilling home from six yards on the half hour mark.
But Dundee levelled with a terrific strike from Josh Mulligan whose shot from the edge of the box found the left-hand corner of the net.
With 20 minutes left, substitute John Smith smashed the ball into the bottom right-hand corner.
However, only a superb save by Jackson from Murray’s close-range effort prevented United equalising.