Stand-in skipper Sean O'Hanlon headed the only goal as MK Dons returned to the top of League 2 with a win at Grimsby.

O'Hanlon rose to head home Colin Cameron's ninth-minute corner as the Dons struck the first blow in a weekend that could prove pivotal in the race for League 2 promotion.

The result edges the Dons a point ahead of second-placed Peterborough, who could regain the initiative with a win at Dagenham on Saturday.

Then it'll be over to the Dons at Chesterfield on Monday before Posh head for Griffin Park to play resurgent Brentford 24 hours later.

It's a key spell in the season that could go a long way to deciding where the prizes will be dished out come May.

And the Dons gave themselves the perfect start with another impressive away performance at Blundell Park.

Sean O'Hanlon rises above Rob Atkinson to power home the only goal.

From first minute to last, Paul Ince's team oozed professionalism as showed why they're the team that has set the pace in the division since September.

While never quite at their brilliant, incisive best, the Dons were too much for a Grimsby side that will have to produce a lot more if they're to make the Johnstone's Paint Trophy final at Wembley more than a stroll for the men from MK.

Rarely did Ince's side, still without suspended captain Keith Andrews and the injured Mark Wright, have to get out of third gear and even rarer were Grimsby good enough to make them.

When the Mariners did get themselves into decent positions, they found the combination of O'Hanlon and Danny Swailes too much to overcome.

Had the home side managed to keep a lid on the visitors early on, they might have given themselves a chance to blossom. But those plans were blown apart when O'Hanlon struck just nine minutes in.

The defender's header from Cameron's left wing corner always looked destined for the net, only a desperate black and white shirt prevented it from nestling there but the ball was a good foot over the line.

Jordan Hadfield holds off his marker.

The perfect start for the Dons, who saw their chance to dominate and duly did so.

Lloyd Dyer constantly provided Grimsby with work to do as he probed away down the Dons right, ably assisted the positive runs of full-back Carl Regan.

With Cameron and Alan Navarro bossing the midfield, the Dons never looked in any trouble during the first period, despite failing to create many clear-cut chances.

Grimsby were struggling to put more than a few passes together and, such was the Dons dominance, a second goal seemed a formality despite the lack of outright openings.

John Miles nearly provided it just before the break when he burst into the box onto Lloyd Dyer's pass, but Phil Barnes in the Mariners' goal produced an excellent one-handed save to deny him.

Whatever Alan Buckley said to his players at the break seemed to do the trick as Grimsby came out like a different side.

Defender Rob Atkinson wasted a decent headed chance from a Nick Hegarty corner two minutes into the second period and the home side immediately started to look more threatening.

Jemal Johnson tends to thrive on such environments and, having just shown flashes of ability in the first period, the pacy Dons forward came into his own as the game became more open.

Jamie Clarke and Tom Newey both curled free-kicks wide of Willy Gueret's goal as Grimsby continued to probe for an opening but Johnson was causing them problems.

Obviously benefiting from the arrival of Aaron Wilbraham off the bench, the striker making his first appearance in four weeks due to a knee injury, Johnson grabbed his opportunity to roam with both hands.

Time and again he provided the outlet for Dons players under pressure, peeling away to the left flank to hold the ball up, run at the defence and give his hard-working defenders time to breath.

Had their been a better final product from the American-born forward, the Dons could have had four or five but his pure enthusiasm to run and boundless energy made him impossible to criticise.

Having thrown on strike pair Gary Jones and Martin Butler, Buckley was nearly rewarded for his positive move when the latter slid the former into a shooting position on 73 minutes.

But Jones turned onto his right foot as he arrived in the box, a move than gave Swailes just enough time to slide in and block the shot.

Dean Lewington and Jemal Johnson cause Grimsby problems down the Dons left.

It was hardly a backs-to-the-wall defending from the visitors, in fact most of the play was in the Grimsby half of the pitch as the Dons looked set to stroll to three points.

But there was worse to come in stoppage time as Grimsby came within inches of not only nicking a point, but winning it.

Jones was given space to cross from the right after Johnson was outmuscled in midfield, and when the substitute's cross was met at the far post by Nick Fenton, a goal looked the only result.

Willy Gueret had other ideas, scrambling across his goal to make a crucial block with his feet and prevent a disastrous equaliser.

Having had little to do for 90 minutes, the Frenchman's powers of concentration were as impeccable as ever.

Had Butler been more accurate with his header from Newey's cross a minute later he might have been forced to prove that again.

Three more points takes the Dons to 72 for the season with 11 games to play, while their 13 wins on the road is unmatched by anyone.

The gauntlet has been laid down to Peterborough as the finishing line hazily looms over the horizon.

Who will blink first?

Grimsby Town (4-5-1): Barnes, Clarke, Fenton, Atikinson, Newey, Till (Butler 46), Boshell, Hunt, Bolland, Hegarty, Bore (Jones 46)

Subs not used: Montgomery, Whittle.

MK Dons (4-5-1): Gueret, Regan, O'Hanlon, Swailes, Lewington, Dyer (Livermore 69), Hadfield (Wilbraham 60), Navarro, Cameron, Miles (Stirling 85), Johnson.

Subs not used: Abbey, Baldock.