In a quiet first half El-Hadji Diouf looked lively as he repeatedly asked questions of the Saints defence but failed to make the crucial breakthrough.
However, it was Southampton who had the best chance of the half as Billy Sharp failed to hit the target from close range following good work from Daniel Fox.
The second period continued in much the same fashion but Sharp got the first goal of the game as he finished smartly past Carl Ikeme.
Sharp's goal brought the game to life and the striker put some distance between his side and Rovers in the 75th minute as he took advantage of some questionable defending before placing his shot in the bottom corner.
Doncaster improved in the closing stages but Sharp's brace was enough to secure the points for Southampton.