Millwall recorded another comprehensive away victory in a vital basement battle at the Keepmoat on Tuesday night.
Early goals from Andy Keogh and Harry Kane put The Lions in the box seat, and from that point there would only be one winner.
Darius Henderson bagged a third on 58 minutes and The Lions saw out the remainder of the game comfortably.
The visitors took the lead on nine minutes when James Henry followed a great run down the right with a perfect near post cross that Keogh met with a downward header for his fifth Millwall goal.
Kane made it 2-0 four minutes later with a 25 yarder, and could have had a third with a volley that fizzed just wide.
Left back Tommy Spurr went closest for Donny with two efforts just off target before the break, but Maik Taylor didn't have a difficult save to make all night.
Henderson wrapped up the scoring with a flick into the far corner from another Henry cross.
Hendo had brought a brilliant save out of Carl Ikeme just prior to his strike, but at the other end Maik Taylor remained a virtual spectator throughout, fielding tame second half efforts from Barnes and Diouf.
After the bizarre events at Elland Road on Tuesday night, Saturday's encounter with Leeds United at The Den should be interesting to say the least.
Kenny Jackett deserves great credit for the way he has continued to motivate his side to play attractive winning football on their travels. How to transfer that form to The Den is the question he will be keen to answer this weekend.
Doncaster Rovers: Ikeme, O'Connor, Spurr, Bird, Beye, Gillett, Hayter (Oster, 57mins), Barnes, Diouf (Robert, 78mins), Piquionne, Coppinger (Dumbuya, 77mins). Subs not used: Woods, Bagayoko.
Booking: Diouf (60mins)
Millwall: Taylor, Smith, Robinson, Ward, Craig, Henry (Feeney, 67mins), Wright (Montgomery, 88mins), Abdou, Henderson, Keogh, Kane. Subs not used: Forde, Dunne, Bouazza.
Booking: Robinson (59mins)
Scorers: Keogh (9mins), Kane (13mins), Henderson (58mins)
Ref: S Attwell
Att: 7,572 (away 301)