Two goals in five second-half minutes saw struggling Millwall come from behind to beat Derby at The New Den.

Substitute Marvin Williams was the Lions hero, coolly slipping the ball home in the 78th minute after Marvin Elliott had headed an equaliser.

Seth Johnson's third goal in two games opened the scoring for the Rams, who are now looking over their shoulders in the lower reaches of the Coca-Cola Championship.

Millwall, buoyed by a 2-1 win at Brighton on Saturday, made two changes - Barry Cogan and Elliott preferred to Zak Whitbread and Bruce Dyer.

Derby were forced to make one change from the side which held runaway leaders Reading to a 2-2 draw, Michael Johnson coming in for the suspended Andrew Davies.

Defender Davies, sent off against the Royals, extended his loan deal from Middlesbrough this morning - while striker Danny Graham will stay at Pride Park for a further month.

After a quiet start, the Rams came agonisingly close to opening the scoring from their first chance - but Lee Holmes' shot cannoned back off a post.

Alan Dunne responded for the Lions, flashing a shot past the upright, before the lively Holmes forced a fine stop from Colin Doyle with a 25-yard drive.

The action continued to swing from end to end as David Livermore lobbed inches over the bar, Adam Bolder headed wide for Derby and Elliott drilled a long-range effort high and wide - all in the space of two minutes.

Millwall were looking the side more likely to score as time ticked on, Elliott heading over from a Jody Morris corner and Dunne forcing a diving save from Lee Camp.

The Lions started the second half brightly, Cogan inches away with a shot from just inside the area.

Kevin Braniff fired in an effort from distance which was easily gathered by Camp, and his quick distribution allowed Inigo Idiakez to unleash a fierce 25-yard attempt which had Doyle scrambling.

Tommy Smith forced another superb stop from Doyle, before the Rams broke the deadlock on the hour.

Holmes crossed from the left, and Johnson crashed his header past the goalkeeper for his third goal of the season.

Morris had a free-kick tipped around the post, and Livermore powered a header straight at Camp as the Lions searched for an equaliser.

Shortly afterwards they got it.

Marc Edworthy brought down substitute Josh Simpson - and when Cogan floated in the free-kick Elliott headed home unchallenged from 12 yards.

Williams had replaced Braniff just before the hour and, with just 12 minutes remaining, he fired Millwall ahead.

He showed superb control to bring down a Livermore pass; then he dummied Camp and slotted the ball home to secure a vital win for David Tuttle's men.

Teams

Millwall Doyle, Dunne, Lawrence, Robinson, Craig, Elliott, Morris (Simpson 68), Livermore, Cogan, May, Braniff (Williams 59).

Subs Not Used: Phillips, Whitbread, Dyer.

Goals: Elliott 73, Williams 78.

Derby Camp, Edworthy, Nyatanga, Michael Johnson, Jackson, Smith (Barnes 80), Bolder (Peschisolido 80), Idiakez, Seth Johnson, Holmes, Graham.

Subs Not Used: Poole, Doyle, Thirlwell.

Goals: Seth Johnson 60.

Att: 9,523

Ref: M Atkinson (W Yorkshire).