Super sub Carlos Fangueiro stepped off the bench to secure Millwall's passage into the Carling Cup Second Round at the expense of League Two battlers Bristol Rovers.
Portuguese striker Carlos had only been on the field for five minutes when he rose to powerfully head Jamie Vincent's cross into the roof of the net for The Lions' second goal of the game with his first touch.
Barry Hayles had earlier bundled Millwall into a 55th-minute lead, firing home from close range after keeper Scott Shearer had fumbled Josh Simpson's teasing delivery.
The final whistle was met with as much relief as enjoyment, as Colin Lee's charges bounced back from Saturday's Madejski horror show with a solid, if unspectacular display.
In the circumstances, that was perhaps the main priority; getting the win, keeping a clean sheet and boosting the confidence ahead of the Championship clash with Ipswich Town this weekend.
The two teams traded scoring opportunities in an evenly contested opening half.
Alan Dunne's 17th-minute low drive had Shearer at full stretch, whilst three minutes later at the other end, Craig Disley headed narrowly over before the lively Jefferson Louis sent a sizzling shot a foot over.
Ben May flashed a header off target from a Dunne cross as The Lions began to ask questions of the visiting defence, but Rovers nearly stole a shock lead on 28 minutes.
Paul Jones, making his Millwall debut after signing on a month's loan from Wolves, flung himself acrobatically to fingertip Louis' goalbound header away for a corner.
James Hunt shot wide and then just before half-time Louis hit a rasping shot that flew inches over.
The turning point of the match came shortly after the restart when Louis, who had proved a real handful throughout, was replaced by Richard Walker.
Two minutes later Simpson sprinted down the left, Shearer made a hash of dealing with the cross under pressure from Ben May and Hayles fired home his first goal of the campaign against his former club.
Don Hutchison, a 65th-minute replacment for Jody Morris, saw his shot cleared off the line 10 minutes after entering the fray before Simpson - so much more positive in the second half - was denied what would have been a stunning solo goal by a brave block from the keeper.
But Millwall didn't have to wait much longer to double their tally courtesy of Fangueiro's excellent header to put the tie beyond Rovers' reach.


Millwall: Jones, Dunne, Vincent, Livermore, Phillips, P. Robinson, Morris (Hutchison, 65mins), Igoe, May, (M. Elliott, 90mins) Hayles (Fangueiro, 79mins), Simpson. Subs not used: Serioux, Craig.
Bookings: Simpson (61mins)
Scorers: Hayles (55mins), Fangueiro (85mins)

Bristol Rovers: Shearer, Ryan, Hinton, S. Elliott, Anderson, Hunt, Lescott, Campbell (Williams, 66mins), Disley (Carruthers, 82mins), Louis (Walker, 52mins), Agogo. Subs not used: Bass, Forrester.
Bookings: Agogo (59mins), S. Elliott ( 76mins)

Ref: Clive Penton
Att: 3,079 (Away: 218)