WHEN Bristol Rovers scored after just three minutes on the opening day of the season, questions were inevitably asked of the Sunderland defence. Suffice to say, they have subsequently been answered.

The Black Cats have played 537 minutes of League One football since Luke Leahy converted from the spot on the opening weekend, and in all that time, their defence has remained unbreached.

Last night’s clean sheet against Crewe Alexandra was their fifth in a row in the league, and was sufficient to earn a second victory in the space of four days.

Luke Offord’s own goal on the stroke of half-time settled things, with the Crewe centre-half turning Lynden Gooch’s low cross into his own net, but it was the quality of Sunderland’s defending that was the truly decisive factor in their latest hard-fought win.

Lee Burge was never seriously threatened as the Black Cats restricted their opponents to a handful of forays into their 18-yard box, and having built his previous promotion successes at Bolton Wanderers and Bradford City on a watertight defence, Phil Parkinson is threatening to repeat the feat on Wearside.

His side spurned a number of good chances to add to their lead last night, most notably when Max Power and Bailey Wright both failed to find the target from promising positions in the second half, but if you are not conceding goals, you do not need to score a hatful to win.

Jack Ross’ Sunderland sides always had a habit of making life hard for themselves by displaying their soft underbelly. The season remains at a formative stage, but Parkinson’s team increasingly looks like it is made of much sterner stuff.

Sunderland’s strong start to the campaign has been built on their defensive strength, and Parkinson will have been delighted to see his side’s resilience remain intact despite a couple of enforced alterations.

Jordan Willis and Tom Flanagan have been key components of Parkinson’s preferred back three since the second half of last season, but with the former sidelined by the foot injury that forced him off at Swindon at the weekend and the latter only ushered on for the final four minutes as a substitute as he nurses an ankle problem, a reshuffle was required.

Conor McLaughlin retained his place after coming in from the cold at the County Ground, while Luke O’Nien reprised the centre-half role that was first trialled in the EFL Trophy win over Carlisle United. Neither is really a natural central defender, but both looked at home as Sunderland successfully contained a Crewe side boasting former Black Cat Mikael Mandron in attack.

With a now fully-revitalised Grant Leadbitter performing his usual sweeping-up role at the base of midfield, the hosts looked rock solid despite their alterations.

The problem, initially at least, was that while they were structurally sound and dominant in terms of possession, they found themselves struggling to break down an opposition rearguard that was as well-drilled as their own.

Neither Charlie Wyke nor Chris Maguire was able to find much space in the final third, so while Gooch and Denver Hume got themselves into some dangerous positions from their respective wing-back berths, they invariably found themselves delivering the ball into a packed 18-yard box.

Wyke turned neatly on the edge of the area before shooting over, and Maguire curled a direct free-kick wide of the target after whipping his shot wide of the wall, but it was the 31st minute before Crewe goalkeeper Will Jaaskelainen, son of former Bolton favourite Jussi, was called into action.

The 22-year-old, who was born in the North-West but represents Finland at junior international level, held on to Wyke’s close-range header, and was involved again a few minutes later as he parried Power’s effort after the midfielder had latched on to Wyke’s lay-off.

With Maguire drilling two long-range strikes narrowly wide in the closing stages of the first half, Sunderland were threatening to make their superiority count, but they were having to work hard and be patient, such was the quality of Crewe’s organisation.

Parkinson has spent most of his time on Wearside preaching the importance of persistence though, and his side’s dominance was finally rewarded in first-half stoppage time.

Gooch, whose driving runs down the right were a key feature of Sunderland’s play all evening, delivered an excellent ball into the box, and while Offord tried to get to the ball ahead of Wyke, he only succeeded in heading into his own net from inside the six-yard box.

Crewe failed to record a single effort on target before the interval, but that changed within four minutes of the restart, albeit without Burge being seriously threatened in the Sunderland goal. Omar Beckles rose highest to meet a corner, but his header looped tamely into Burge’s arms.

The visitors might have posed more of a question had Oliver Finney not over-run the ball when he was released into the area a couple of minutes later, but that was really as good as things got for the visitors, who are still feeling their way into League One after their promotion from the fourth tier last season.

Power wasted a good chance to double Sunderland’s advantage when he blazed over from inside the area after Wyke’s blocked shot rebounded into his path, and both Hume and Gooch fired relatively tame efforts straight at Jaaskelainen as the Black Cats continued to push for the second goal that would have made their night more comfortable.

Their best opportunity to double their lead went begging midway through the second half, with Wright somehow failing to find the target from no more than three yards. Gooch swung an inviting free-kick into the area, but while a diving Wright got his head to the ball, he was unable to direct his effort under the crossbar.

It was a bad miss, but in truth, it never really looked like being an especially costly one, with Crewe’s occasional counter-attacks tending to break down through a combination of poor decision-making and astute covering defending from Sunderland.

Leadbitter produced an excellent example of the latter with quarter-of-an-hour left, sliding in on the edge of the area to block Charlie Kirk’s shot. The Wearsider’s reading of the game remains as impeccable as ever, and his return to the ranks after last season’s absence because of personal issues is a major factor in his side’s ongoing defensive success.

While Crewe tried to throw men forward in the closing stages, they never really threatened to fashion a successful comeback and the hosts were able to cruise to the final whistle with a minimum of fuss.

There will be much tougher tests than this in the rest of the season, but a trouble-free 1-0 win is never to be sniffed at and recent Sunderland sides have been similarly dominant in games, only to end up drawing 1-1.

Parkinson’s side rarely look conceding, so while issues remain in attack, with none of their strikers making an unanswerable claim for a run in the team, the wins continue to rack up.