Inside the big gamble that kept Sunderland's play-off dream alive as a familiar hurdle is overcome

Which is not to say that Sunderland were playing badly, necessarily. It was just that the game being played was so familiar, and had settled into a pattern we have seen too often since the turn of the year.

Birmingham City came and applied no pressure on the ball, at least when it was in Sunderland's backline. Only when the Black Cats played the ball into midfield did they snap into life, and to their credit they did so with real vigour. When they won it back, they sprung clear with what at times was genuinely quite blistering pace. George Hall, Reda Khadra and particularly Tahith Chong were all causing problems, and there were spells where with just a touch more clinical finishing the game could have got away from Tony Mowbray's side.

This has been the way many sides have approached playing at the Stadium of Light since that chastening afternoon against Stoke City, and Birmingham were one of the sides with the athleticism to execute it.

Without a target to play off or someone to hunt the ball down in the channel, Sunderland can find themselves with all of the ball but not enough threat. Mowbray has spoken in recent weeks about finding a balance to correct his side's poor home form, putting the opposition under pressure but doing so without leaving behind the space which leaves them vulnerable.

In the first half, salvation came from the most unlikely of sources: a set-piece goal. Without Stewart, Simms and now Ballard, it has been a constant source of frustration for Sunderland who generally give up a significant advantage in both height and physicality to their opposition. Here, to their credit, they made it work with a series of inventive routines that eventually caught Birmingham out. They had come close when Patrick Roberts' flick just evaded Jack Clarke, and went one better when Roberts turned Batth's header to Trai Hume at the back post.

Both head coaches identified this as a crucial moment in the game, a major boost for Sunderland that completely changed the complexion of the task in front of them.

All the same, the second half had started with the pattern of play much the same and for those first fifteen minutes or so, there was nothing on the pitch to suggest that a home winner was an inevitability.

So it was with around half an hour to play that Mowbray turned to his coaching staff to debate what to do next, and the decision was that in the circumstances it made sense to gamble. With a draw doing very little to help Sunderland, they opted to risk losing the game in order to try and create the space that could allow them to win it.

The upshot was that the Black Cats dropped Alex Pritchard and Patrick Roberts deep into central midfield, leaving Dan Neil to deal with any counterattacks pretty much on his own. Birmingham had chances, but almost immediately the hosts were beginning to play around the midblock that had caused them so many issues for so much of the game. It almost yielded one of the goals of the season, a delightful 1-2 between Roberts and Joe Gelhardt undone only by an untimely bobble that forced the former to turn his effort over the bar.

Sunderland now had space, and what they have always had this season is individual quality. A superb switch of play from Clarke, creating one of the few moments where Amad was allowed to gather the ball with both time and space. Birmingham's recovery was actually good, Hannibal bursting back to get in and help out his full back, who by and large came out of his battle with Amad in credit. This time, though, the winger's footwork was too sharp and the finish far too precise for John Ruddy.

Sunderland had to do it the hard way, after that. Chong's persistence down the right flank eventually told, Dennis Cirkin shown a second yellow card which left his side with much work to do in the final fifteen minutes. They did it hearteningly well - the introduction of Luke O'Nien to the backline in that crucial double substitution had brought them a bit more urgency on the ball and now it brought them another player willing to put their body on the line in the closing stages. One tempting cross from Hannibal almost yielded an equaliser, but generally the chances for Birmingham City were few and far between.

And so the season rolls on, Sunderland still very much in the mix. They will face a similar challenge on Tuesday night, against a Huddersfield Town side still very much fighting for their Championship status and who will almost certainly defend deep and let the hosts have the ball. It's a game that the Black Cats almost certainly need to win, if they are to achieve Mowbray's goal of giving the support something to dream about right until the very last day at Preston North End.

For the Black Cats boss this delicate balancing act will continue, trying to maintain an attacking threat while having the defensive structure that has been so impressive away from home been so impressive.

The odds are probably still against his side, but this was a win that embodied how well they have done to stay in the race. Again, as they have done with impressive frequency, they found a way.