Rovers made hard work of it against the bottom club after making a flying start with two goals in the first 18 minutes, but they finished worthy winners, despite not being at their best to clinch their 12th victory in the last 15 games.
Last season's top scorer Paul Heffernan - just back from injury - scored for the second game in a row to put Doncaster on the path to victory.
It was a superbly-taken goal by the Irish striker, who chested down a right-wing cross from James Coppinger and controlled the ball skilfully before hammering it home off the underside of the crossbar.
Doncaster made it 2-0 seven minutes later when big striker Mark McCammon scored with a shot on the turn from close range, after Heffernan and Coppinger had both had efforts blocked.
At that stage it only looked a question of how many for Doncaster, especially after Paul Green had gone close to adding a third with a fierce angled drive in the 33rd minute.
But Vale showed their mettle when they hit back a minute later to stun the home fans into silence with a goal from Danny Whitaker.
The ball broke to the hard-working midfielder in the penalty box and he reacted quickest to slam home a shot from point-blank range, before keeper Neil Sullivan could get to the ball.
Doncaster were unlucky not to add to their lead when McCammon headed a superb free-kick from Green against the crossbar in the 41st minute, before Matt Mills was denied when visiting keeper Joe Anyon tipped another terrific effort on to the crossbar on the hour mark.
But Vale almost snatched an unexpected point in the 71st minute when Chris Herd hit the foot of the post with a left-foot shot.