Millwall moved to within three points of the play-offs with their first home win since Boxing Day as the Londoners capitalised fully against a team with one of the worst away records in the Championship.
However, the Lions player-manager, Dennis Wise, then took the opportunity afterwards to criticise the board for not supporting him earlier this season in their push for promotion.
Wise said: "Nine games ago I needed support and didn't get it [for players] and now the time has gone. I hope this is not a missed opportunity but we won't know until the end of the season." It was a thinly veiled attack on the change of regime at the club which will see the chairman and Wise's friend, Theo Paphitis, leave this summer, to be replaced by Jeff Burnige.
Despite his problems, Millwall were never in difficulty against Argyle, and it took two goals in the space of seven second-half minutes to justify the home side's superiority, Peter Sweeney having given them the lead after a quarter of an hour.
The midfielder's first goal of the season had fortune surrounding it as Barry Hayles' pass was intended for Danny Dichio, who looked offside six yards out. He missed the ball, but it ran for Sweeney who had gambled on such an eventuality.
Hayles later had the goal his efforts deserved. A long clearance was headed on by Dichio to his team-mate, who slotted his shot under Luke McCormick.
Millwall's third arrived when David Livermore sent a cross to the far post, where Dichio dispatched a header into the top corner to leave Argyle looking towards the relegation zone.
Goals: Sweeney (15) 1-0; Hayles (56) 2-0; Dichio (63) 3-0.
Millwall (4-4-2): Marshall; Robinson, Lawrence, Ward, Craig; Sweeney, Morris (Elliott, 50), Livermore, Simpson (Quigley, 73); Dichio (May, 86), Hayles. Substitutes not used: Serioux, Peeters.
Plymouth Argyle (4-4-2): McCormick; Connolly, Coughlan, Aljofree, Gilbert; Norris (Blackstock, 90), Wotton, Buzsaky, Gudjonsson (Capaldi, 66); Evans (Chadwick, 68), Taylor. Substitutes not used: Lasley, Doumbe.
Referee: P Melin (Surrey).
Booked: Plymouth Argyle Gudjonsson.
Man of the match: Simpson.