Birmingham climbed into the First Division play-offs with an emphatic victory over Grimsby, who saw their seven-game unbeaten run come to an abrupt halt at St Andrews.

Midfielder Bryan Hughes took his tally for the season to eight goals with two well-taken first half strikes.

Second half goals from Stern John and Damien Johnson then wrapped up all three points for Steve Bruce's men.

The home side knew a win would move them above Midlands rivals Coventry and into the top six after the Sky Blues had lost 2-1 at Sheffield Wednesday the previous night.

Victory was no more than Birmingham deserved as new signing Michael Hughes, signed on loan this week from Wimbledon, ran the midfield and inspired his new team-mates to one of their best performances of the season.

With defender Olivier Tebily, a £700,000 signing from Celtic, also on top of his game, Birmingham looked assured at the back.

Grimsby had seen their recent form move them out of the relegation picture but when they forced any openings against Birmingham they found goalkeeper Nico Vaesen on form.

Grimsby's Stuart Campbell tested Vaesen after 10 minutes, following a poor header by home defender Michael Johnson, with a dipping volley which the keeper tipped over the bar.

Michael Boulding then went on a strong run on the quarter-hour which took him past Tebily and Michael Johnson and Boulding's square ball set up Danny Butterfield whose shot from the edge of the area was beaten away by Vaesen.

Stan Lazaridis brought a save out of Danny Coyne after 21 minutes with a far post header from Damien Johnson's cross following good headers from John and Tommy Mooney.

And Birmingham were ahead a minute later after Jeff Kenna's deep cross had been headed back by Mooney. Grimsby player-manager Paul Groves failed to clear the loose ball and Bryan Hughes picked his spot from 15 yards for his seventh goal of the season.

Mooney should have made it two five minutes later but his close-range shot was blocked by Coyne after Lazaridis had crossed low from the left.

Bryan Hughes got his second of the game on the half-hour when Lazaridis crossed again from the left and Mooney could not accept the chance. Hughes was waiting for the ball and kept his cool to slot the home low into the bottom corner.

Lazaridis thought he had been given the chance to make it three but was given offside before Coyne went down low to his left to stop the Australian walking the ball into the net.

Tom Williams, making his home debut since a £350,000 move from Peterborough, floated in a deep cross from the left just four minutes into the second half and Birmingham went further ahead. John rose unmarked to head across Coyne into the far corner for his fifth Birmingham goal.

Birmingham made it four when former Blackburn player Damien Johnson scored his first goal for his new club when he charged down Tony Gallimore's clearance and ran on unchallenged to slot the ball through Coyne's legs.

Gallimore was booked a minute later when he bundled over John. Michael Hughes was then just wide with a low free-kick as Birmingham began to run riot.

But Grimsby wasted a chance to pull a goal back when Boulding shot wide after a mix-up in the home defence set up his chance.

Birmingham substitute Geoff Horsfield should have done better when he won the ball off Groves but saw his shot blocked and referee Paul Taylor stopped play because Coyne was injured battling for the loose ball.

And Grimsby knew their bad day was complete when substitute Paul Robinson broke clear on the left but fired wide of Vaesen's right hand post with only minutes remaining.

Mooney should have made it five but Coyne blocked his shot after he broke clear. But there was nothing wrong with Birmingham's earlier finishing as two goals either side of half-time put them on course for a fourth visit to the end of season play-offs.

Teams

Birmingham: Vaesen, Kenna, Tebily, Michael Johnson, Tommy Williams, Damien Johnson (Eaden 74), Bryan Hughes, Michael Hughes (Carter 78), Lazaridis, John (Horsfield 66), Mooney.

Subs Not Used: Bennett, Woodhouse.

Goals: Bryan Hughes 22, 31, John 50, Damien Johnson 64.

Grimsby: Coyne, McDermott, Todd, Groves, Gallimore, Butterfield, Pouton, Coldicott (Burnett 69), Campbell, Allen (Falconer 56), Boulding (Robinson 80).

Subs Not Used: Ford, Croudson.

Booked: Campbell, Groves, Gallimore.

Att: 23,249

Ref: P Taylor (Cheshunt).