PHIL PARKINSON has spent most of the transfer window trying to shuffle the pack of strikers at his disposal, but as tomorrow’s deadline draws near, he might well be reflecting that his trump card has been leading the line all along.

Will Grigg and Marc McNulty have been cast aside on Parkinson’s watch, and could leave Wearside in the next 24 hours, but Charlie Wyke has emerged as the one constant in Sunderland’s attacking line-up since the turn of the year and his importance was underlined as he took the one chance that came his way to settle a game that was every bit as unattractive as the pock-marked Prenton Park pitch.

Wyke headed home Chris Maguire’s 60th-minute free-kick to lift the Black Cats back into the play-off positions, and while he might have been signed under Jack Ross, his ability to lead the line is becoming increasingly crucial to Parkinson’s preferred style of play.

Sunderland’s watertight defence is also becoming increasingly important, with last night’s shut out making it four games in a row without conceding a goal. Having been incapable of keeping a clean sheet for much of the first half of the season, the Black Cats’ defenders have clearly benefited from Parkinson’s work on the training ground. Aside from having to make one first-half stop from Kane Wilson, Jon McLaughlin went through the whole of last night’s game without being threatened.

“The work on the training ground is showing with the defenders, but to get clean sheets, it’s not just about the defenders and the goalkeeper, it’s about the whole team working for each other and I felt we did that and earned it,” said Parkinson. “We had to defend a lot of set-plays, especially towards the end when the referee was giving a lot of free-kicks we didn’t agree with. You’ve got to defend those situations, and I go back to my first game away at Wycombe when we conceded from one of those set-plays. That’s the difference.”

Given the state of the Prenton Park pitch, this was never going to be a night for free-flowing football. Having cut up badly during Sunday’s FA Cup thrashing at the hands of Manchester United, Tranmere’s playing surface was like a cross between a ploughed field and Roker beachfront, such was the combination of sand and mud.

The lack of quality on display was understandable, although the first half in particular still proved a difficult watch. Passes went astray, long balls sailed over the touchline and minutes on end were devoted to a series of wrestling matches that referee Antony Coggins proved incapable of policing. Creativity, or even anything that came close to it, was all but non-existent, although to Sunderland’s credit, they overcame the crater-filled conditions to emerge with all three points.

“We had to do what we had to do, it was as simple as that,” said Parkinson. “It was never going to be pretty, but we had to be resilient and I felt we were. We got our rewards.”

Chances were at a premium all night, although Sunderland should really have scored after just five minutes. Bailey Wright was making his first Black Cats appearance at the heart of the back three, having dislodged Alim Ozturk from the starting line-up, and the centre-half should have got his Sunderland career off to a flying start with virtually his first touch.

Joel Lynch nodded Chris Maguire’s early free-kick into Wright’s path, but he could only prod wide of the target at the far post. Given that he was inside the six-yard box, it was a golden opportunity.

At the other end, Morgan Ferrier was trying to barge his way through the Black Cats’ backline, but to their credit, Wright and Jordan Willis stood firm.

They were undone in the eighth minute, with Wilson releasing Kieron Morris behind the Sunderland defence, only for the Tranmere midfielder’s touch to let him down as the ball ran harmlessly through to McLaughlin.

McLaughlin was called into action midway through the first half, palming away Wilson’s curled free-kick from the corner of the 18-yard box, but this was not a night when either goalkeeper was overworked.

It was an evening when players had to graft, and while they might have been unable to exert much of an attacking influence, Sunderland’s midfielders deserve credit for the way in which they ran themselves into the ground to protect those stationed behind them.

Power, returning to the ground where he started his career, was especially industrious, covering superbly ten minutes into the second half to prevent Ferrier breaking into the box after he spun away from Wright. It proved a crucial intervention, as just five minutes later, Sunderland were claiming the lead.

Given the difficulty in playing the ball on the floor, it was no surprise at all that the breakthrough came via a set-piece, with Maguire delivering an excellent free-kick from the right-hand side.

Wyke had barely been in the Tranmere six-yard box in the opening 59 minutes, but having eased himself in front of his marker at the front post, he glanced a deft close-range header past Davies. It was his fifth goal of the season, and more than justified his continued presence in the side ahead of recent signing Kyle Lafferty.

Sunderland saw things out from that point on with a minimum of fuss, with their task made easier by the 84th-minute dismissal of Manny Monthe. The Tranmere defender was harshly sent off for two yellow cards after what looked an innocuous challenge on George Dobson.