Two goals from Neil Harris and one from Dion Dublin handed Millwall a play-off date with Birmingham after a comfortable 3-1 victory a the New Den.

Dublin set the Lions on the way stabbing home after only five minutes and Harris added further goals in the 23rd and 31st minutes.

Danny Butterfield had equalised from Grimsby on 11 minutes, but the one point the Lions needed to secure a play-off berth was never in any danger after that.

Birmingham defeated Sheffield United at St Andrews to secure a mouth-watering play-off date between clubs from England's two biggest cities.

The first leg will be in Birmingham next Sunday as the Blues go into the play-off hat for another season with the second leg at the New Den the following Wednesday 1 May.

Millwall got off to the perfect start when on-loan striker Dublin put the Lions ahead in the sixth minute.

The home side got the ball out wide when Paul Ifill spilled it out to Matt Lawrence on the right.

The defender crossed wickedly right-footed and the wily Dublin nipped in ahead of Andy Todd.

The veteran marksman prodded the ball through the legs of Danny Coyne in the Mariners goal for the opener.

However Millwall's jubilation was short-lived when Grimsby hit back five minutes later to equalise.

Stacey Coldicott collected the ball on the edge of the Lions' penalty and thought of shooting goalwards.

Instead the Mariners' midfielder lifted the ball over the Millwall rearguard and Butterfield stroked home only his second goal of an unprolific season.

Lions unleashed

The vocal home fans did not have to wait long for their side to regain their advantage though. In the 23th minute Steven Reid sent in a long throw into the Grimsby box.

Dublin once again used all his experience and flicked the ball onto Neil Harris.

Harris headed the ball back across Coyne's goal and the Welshman could only palm the ball into the corner of his net.

Eight minutes later, Harris put the home side further ahead.

Again it was caused by a Reid long throw, this time on the Millwall right.

Again it was Dublin who flicked it on but this time Iain Ward, making his Grimsby debut, could only help the ball onto Harris.

The Millwall striker fashioned a wll-placed right-foot volley that was accurate enough to sneak in the far corner of Coyne's goal.

Millwall manager Mark McGhee replaced Dublin with another veteran striker Steve Claridge at the break.

The former Manchester United, Coventry and Aston Villa striker needed treatment after a clash of heads moments before the interval.

Millwall played out the rest of the game at a leisurely pace but are now just three games from the Premiership after being promoted from Division Two just last season.

Millwall: Warner, Lawrence, Nethercott, Ward, Bull, Ifill, Cahill, Livermore, Reid, Harris, Dublin.
Subs: Gueret, Ryan, Bircham, Dyche, Claridge.

Grimsby: Coyne, Ward, Groves, Todd, Chapman, Cooke, Coldicott, Pouton, Butterfield, Boulding, Allen.
Subs: Croudson, Raven, Burnett, Robinson, Livingstone.

Referee: A Butler (Sutton-in-Ashfield)