The result means Lions caretaker boss Willie Donachie maintains his unbeaten run at home.
Yet the visitors nearly snatched it at the death as substitute Paul Heffernan hit the post.
It hardly had all the makings of an entertaining contest given both teams had averaged less than a goal per game in League One this season.
However, after a scrappy opening Doncaster made several forays into the Millwall penalty area with Jason Price going close with a header that was tipped over the bar by keeper Lenny Pidgeley.
The breakthrough came in the 17th minute as Lewis Guy slipped the ball through to Jonathan Forte, who was allowed too much space to have a shot on target.
Even so, it was a fine left-foot strike from some 20 yards that flew passed Pidgeley into the far corner of the net.
At this point Millwall were all at sea. Injuries have clearly played their part in the south Londoners bad start to the season, but even that couldn't excuse some a clueless opening 25 minutes from the home side.
Gradually they clawed their way back into the match and equalised just before half-time.
Ben May latched on to a loose ball just inside the Rovers penalty area. His shot was parried out by Ben Smith and the rebound fell invitingly for Darren Byfield to score with a simple tap-in from six yards out.
Byfield almost made it two after the break only for Smith to deny him at full stretch with the save of the match.
Just as it looked as if Millwall but in the ascendancy, former Lions forward Mark McCammon found Price, who had jinked his way into the Millwall penalty box.
Millwall paid the price for backing off and allowing the Rovers forward to shoot as Pidgeley managed to get a hand on the strike but it wasn't enough to stop the ball creeping into the bottom corner of the net.
But Millwall showed enough fighting determination and spirit to hit back again with the goal of the game.
Chris Hackett picked up the ball some 30 yards out on the right and hit a sweet shot that curled beyond the stretch of Smith and into the far corner of the net.
Doncaster continued to test Pidgeley but failed in their attempt to take the lead for a third time to leave the honours even after a thoroughly entertaining 90 minutes.