GIVEN that they were playing against the Mariners, it was perhaps inevitable that Newcastle would have to rely on their skipper to ensure a safe passage into the fourth round of the Carling Cup.

Alan Shearer's 80th-minute winner spared Newcastle's blushes after their best efforts had failed to break down a lively but limited Grimsby side. Despite their opponents' lowly status, the 1-0 success was far from plain sailing.

The win was down to one moment of class from Shearer. Presented with his only opportunity of the game, the 35-year-old drilled a clinical finish past goalkeeper Steve Mildenhall after strike partner Michael Chopra had profited from Gary Bolland's untimely slip.

The goal ensured the Magpies would record their second win of the week following Sunday's derby success over Sunderland, but failed to paper over the cracks exposed by another unconvincing display.

Given the Magpies' dreadful recent record in the Carling Cup - they have failed to reach the last four of the competition since 1976 - Souness was taking nothing for granted against a Grimsby side who accounted for Premiership Tottenham in the previous round.

The Magpies' manager made just four changes to the side that beat Sunderland on Sunday, underlining how important this much-maligned competition is in a season devoid of European football.

Titus Bramble made only his third start of the season, while Chopra partnered Shearer in attack. Souness had been hoping to rest Shearer, given his well-publicised hernia problems, but was forced into a last-minute change of mind after Shola Ameobi became the latest in a long line of Newcastle players to suffer a hamstring complaint.

The United skipper hardly looked like a man in urgent need of surgery as he threw himself around with typical vigour during a first half dominated by the visitors.

With Grimsby's players showing little of the blood and thunder expected of lower-league opponents in the early stages of a cup tie, Newcastle's established internationals were able to dominate midfield from the off.

Even Amdy Faye, normally so tentative in possession, was given time to spray passes far and wide, and his fifth-minute ball to Shearer resulted in an intelligent lay-off that Celestine Babayaro fired straight at Mildenhall.

Grimsby's attacking was far more sporadic, although former Sunderland striker Michael Reddy almost took advantage of Bramble's casual backpass before an alert Shay Given came to the rescue.

That aside, though, there was little to trouble a Newcastle backline marshalled by the ever-improving Steven Taylor and, with Scott Parker providing a constant link between defence and attack, the visitors should have been ahead at the break.

That they were not was due, in the main, to some profligate finishing from Charles N'Zogbia. Faye sent the French midfielder clean through in the 18th minute but, after picking his spot for what seemed like an eternity, N'Zogbia drove against the outside of the post with Mildenhall beaten.

Newcastle would also surely have been a man to the good at the interval had referee Mark Halsey seen Justin Whittle's deliberate elbow in the face of Shearer. The Grimsby defender spent as long sizing up his shot as N'Zogbia but, with Halsey failing to spot the incident, the Mariners were spared a dismissal that would surely have ended their chances.

As it was, the Mariners reached the break on level terms in more ways than one and, while they had failed to match their opponents in terms of possession, United's inability to turn their superiority into clear-cut openings allowed the League Two side to grow in stature.

Consequently, much of the second half was spent with Newcastle struggling to find their way through an obdurate home defence.

With extra-time looming, Grimsby were punished for their first mistake of the match. Midfielder Bolland slipped, allowing Chopra to break down the right and pull the ball back for Shearer to score with a powerful drive.

* A dozen protesters attempted to stage a demonstration during the latter stages of Manchester United's 4-1 Carling Cup victory over Barnet at Old Trafford last night.

Stewards moved in quickly to prevent the protesters unfurling a banner but, after the demonstrators had made their way through the exits, they quickly returned in similar noisy fashion.

Although there was no obvious way of knowing the exact nature of their protest from a distance, the were dressed in similar fashion to the members of the Manchester Education Committee, who invaded the pitch during a reserve team match with Birmingham almost a year ago in direct protest at Malcolm Glazer's £790m takeover.

* Steve Bruce hopes a nerve-jangling Carling Cup victory over Norwich will prove the launchpad for Birmingham's season.

A stunning strike five minutes from time by on-loan Chelsea midfielder Jiri Jarosik secured a place in the last 16 and clinched a first home win of the season.

But more importantly it will provide a big lift to the confidence before Saturday's clash with fellow bottom-three club Everton at St Andrews.

Bruce said: ''I suppose you could say tonight was about the result. I think the best team won but we certainly made hard work of it.

''The five minutes before half-time when we conceded a goal by a deflection when in control and then missed a penalty just about summed us up.

''But we stuck at it. It was a great goal from Jiri and we hope that can be the springboard we are looking for."

Result: Grimsby Town 0, Newcastle United 1.

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