Substitute Conor Sammon’s ninth goal of the season rounded off the 2012/13 campaign with maximum points and top-half finish for the Rams.
The 26-year-old raced onto Jamie Ward’s through pass before coolly slotting the ball under the onrushing David Forde to seal tenth position in the Championship.
Jeff Hendrick almost had the home side off to a flying start when neat build up, including an exquisite touch from Chris Martin, culminated in the Irish midfielder’s tame effort from 20-yards falling wide of goal.
With Millwall’s npower Championship survival still in the balance ahead of proceedings, the Lions were understandably of an anxious disposition on the field of play – creating minimal clear-cut opportunities in the opening 20 minutes.
At the other end, Will Hughes’ seeming 360 degree vision was causing the Lions’ defence plenty of cause for concern, as on numerous occasions the England Under-21 international threaded perfectly weighted passes on the edge of the penalty area, despite intense pressure from the opposition.
It was the guile of Hughes, combined with the energy and endeavour of John Brayford and Ward that led to the creative midfielder dragging an effort wide after 30 minutes.
10 minutes later, the Rams were denied a carbon copy goal of their opener against Leicester City at Pride Park in March. Ward’s in-swinging free-kick was glanced goalwards by Richard Keogh, however, on this occasion Forde produced a fine save to claw away the central defender’s header.
Millwall’s best effort of the half arrived in stoppage time when Liam Trotter’s half-volley into the turf bounced over goalkeeper Adam Legzdins’ crossbar.
Trotter’s strike was followed up by two second half opportunities for the Lions to ensure their safety, but substitute Jermaine Easter saw his acrobatics cleared off the line by Paul Coutts, before Andy Keogh flicked a corner narrowly over at the near post.
A period where the Rams could not get to grips with Millwall’s physical presence ensued, as the visitor’s midfield continuously outmuscled Derby’s, which allowed the Lions to hurl crosses into the penalty area, although Legzdins commanded his 18-yard box with authority to punch clear.
With Millwall’s physicality perhaps in mind, Nigel Clough moved the tireless Bryson into the middle of midfield, with Ward deployed out left, and the Scottish international’s energy created an opportunity for himself, but his low drive took a deflection before falling into the arms of Forde.
In the 82nd minute Gordon Guthrie received a resounding applause from the Rams’ faithful, and four minutes later Sammon’s late winner followed up the touching moment.
The Republic of Ireland international latched onto Ward’s clever pass to roll the ball beyond Forde, which ensures the Rams finish the campaign in the top half of the npower Championship.
Derby County: Legzdins; Brayford, Keogh, Buxton, Roberts; Coutts (Davies 87), Hendrick, Hughes, Bryson; Ward (Freeman 90), Martin (Sammon 80).
Subs not used: Fielding, Bennett, Freeman, Jacobs, Hanson.
Millwall: Forde; Dunne, Shittu, Beevers, Lowry, St Ledger (Woolford 89), Feeney, Batt (Easter 21), Trotter, Wright (Abdou 51), Keogh.
Subs not used: Taylor, Smith, Osborne, Marquis.
Attendance: 25,021 (1,054 visiting supporters.)