The race for Premier League survival is beginning to heat up as we cross over into the second stage of the season, with just five teams now involved.

For Sunderland, it's been season after season of fighting to avoid the drop, continually managing to preserve their top flight status despite coming incredibly close to Championship football on an annual basis.

Currently occupying 19th place in the table, albeit still just one point away from safety, it is looking increasingly likely that the Black Cats will find it difficult to achieve the same feat this season.

As has been so often the case, David Moyes' men tend to start their survival bid towards the end of the campaign. So far, they have only managed four wins from the 21 games they have played, losing 14.

But we reckon the Black Cats' luck might just run out this season. Here are five reasons why...

The Defence

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The back line has been the one of the reasons behind the Black Cats' involvement in constant relegation scraps. This term is no exception as David Moyes' men have the joint-third worst defensive record in the league with a whopping 40 goals conceded from 21 games.

The only good thing at the back for the Sunderland so far this season has been the emergence of young shot-stopper Jordan Pickford, who hasn't been helped by the poor showings of Lamine Kone and Papy Djilobodji in front of him.

Another issue is left-back Patrick Van Aanholt, who is better at attacking than defending. Because of this, the back line tends to get found out too often in games.

It remains to be seen whether the ex-Everton boss will try to bring in defensive reinforcements before the January window closes. Either way, the Black Cats have to stop conceding silly goals if they want to survive another relegation fight.

Home Form

This is key for any side who wishes to survive the drop. David Moyes' team have done little to make the Stadium of Light a fortress this term with just three wins from the 11 games they have played, losing six.

Burnley at Turf moor is a good example of a team wanting to preserve their league status via home form. Sean Dyche's men are currently in 10th place, 10 points away from the drop zone despite having the worst away record in the league.

The Black Cats are not in the same class at the Stadium of Light and need to turn their home form around quickly.

Lack of goals

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Goal scoring is always an issue for a side fighting relegation and Sunderland are currently the joint-third lowest scorers in the league alongside Hull City with 20 goals from 21 games. The Black Cats have struggled to find the net with only Jermain Defoe proving sharp enough to score 12 times.

The squad is full of players without a league goal this season - no less than a staggering 18 have failed to find the net.

The squad looks short of ideas, creativity and determination and consequentially appears destined for life in the Championship next season.

Over-reliance on Defoe

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Arguably Sunderland's best signing in recent years, Jermain Defoe is having another good season after proving so instrumental in the Black Cats' survival last term. The ex-Tottenham star scored 15 league goals last season and has continue to prove his worth in 2016/`7, even at age of 34, with 12 league goals.

That feat has seen him score 60% of his side's league total this term. They are heavily reliant on the veteran's goals and that could prove costly should he pick up an injury between now and May.

The other attacking options alongside the ex-England man such as Fabio Borini and Victor Anichebe have not done enough, netting just four league goals combined.

Poor impact of summer signings

The Black Cats followed the appointment of David Moyes in the summer with the signing of nine players. Donald Love, Mika, Paddy McNair, Didier Ndong and Papy Djilobodji moved with transfer fees involved, Steven Pienaar and Victor Anichebe joined as free agents and Man United's Adnan Januzaj and Man City's Jason Denayer arrived on loan deals.

But none of these signings have been particularly influential for Sunderland, with the acquisition of ex-Chelsea defender Papy Djilobodji still a mystery.

The ex-Nantes man has been at fault for a number of goals with poor positioning exposing the brilliant Pickford far too often. David Moyes and Sunderland have really gotten their transfer recruitment policy all wrong this term, leaving the Black Cats with the weakest squad in the league.