After a scoreless opening period, in which new signing Thorirann Kristjansson showed a couple of neat touches, the visitors took the lead in the 55th minute when defender McMANUS scrambled the ball home following a corner.
With a quarter of an hour remaining, the Bhoys secured the victory when former Livi man FERNANDEZ took full advantage of a mistake by Andrew Considine to slot the ball past debut keeper Sasa Ilic. Considine was one of two Dons to be yellow carded, joining Derek Adams in the referee's book.