Gary Alexander opened the scoring after eleven minutes but although dominating the contest the tourists had to wait until the 70th minute before they struck their second through Chris Hackett. 90 seconds later Hackett set up Neil Harris, who hit the third with a poweful diving header. Ashley Grimes completed the rout with the fourth on 79 minutes.
Boss Kenny Jackett used the game to give almost all his squad a run out, fielding virtually two different sides in each half.
Millwall first half: David Forde, Jack Smith, Tony Craig, Andy Frampton, Scott Barron, Lewis Grabban, Ali Fuseini, Jimmy Abdou, David Martin, Gary Alexander, Steve Morison.
Millwall second half: John Sullivan, Jack Smith (Ali Fuseini, 83mins), Scott Barron, Alan Dunne, Tony Craig (Omar Beckles, 65mins), Chris Hackett, Marc Laird, Adam Bolder, Steve Morison (Kiernan Hughes-Mason, 70mins), Neil Harris, Ashley Grimes.