Who's going down? All permutations as Portugal's relegation battle goes to the last day

A team who have never been relegated from the top flight before, one of the most controversial - even disliked - clubs in Portuguese football, and a team that have finished in the top 8 in each of the last three seasons are all at serious risk of suffering relegation from this season’s Primeira Liga. At least two of them, in fact, are guaranteed to lose their top flight status.

After a tense, tight battle throughout the season, we are down to just three contenders to go down. Each of the three newly promoted teams survived, with Arouca, Vizela and Estoril all having already confirmed their place in Portugal's top flight next campaign. A couple of more established top division outfits are therefore set to depart, including one who to date has never been relegated from the Primeira Liga before.

CD Tondela, since being promoted to the top division for the first time in the club’s history in 2015, have managed to avoid relegation every season, sometimes in quite extraordinary circumstances, earning them the tag of relegation escape artists. This season they face yet another close battle to avoid descending for the first time since their arrival in the big time.

Moreirense, meanwhile, have experienced a nightmare campaign, and the hot-headed Ricardo Sá Pinto at the helm has been unable to rejuvenate a struggling side that have finished 6th, 8th and 8th in the past three seasons. They go into the final day in 17th, well behind the lofty heights the fans have been able to experience in recent years and one point behind Tondela who occupy the relegation playoff spot.

Then there's B-SAD who sit rooted to the bottom of the table with survival hopes highly diminished, but still not entirely extinguished. A controversial club after their infamous split from historic emblem Os Belenenses caused the 1946 Portuguese champions to be relegated to the bottom of the footballing pyramid and saw B-SAD take their place in Portugal's top flight, many have been vocal in their preference as to who they would like to see relegated - but there's still everything to play for.

Here is how the table looks heading into the final day:

With the very best all three teams can hope for being the relegation playoff spot - a tie played between the teams that finish 16th in the top flight and 3rd in Portugal's second division - it could mean that all three teams end up going down, but a 16th place finish does at least provide them a fighting chance of retaining their place among the nation's elite.

Tondela are in the driving seat, safe in the knowledge that victory for themselves will be enough to avoid automatic relegation, but any slip-up will open the door for both Moreirense and B-SAD.

Tondela are tasked with taking on Boavista (11th), managed by former B-SAD manager Petit. That's arguably the toughest match of the three, with B-SAD taking on Arouca (15th), whose top flight status was only confirmed last weekend and who will be delighted to have stayed up with a game to spare. Moreirense then face Vizela (14th), who will also be pleased to have beaten the odds by maintaining their place in the highest division fairly comfortably.

All three matches are winnable, but the side with the most significant chance of slipping up, at least on paper, are the ones situated in 16th, making this an even more intriguing final day.

Here are the combination of potential results - and who would survive automatic relegation in each scenario:

The table illustrates just how unlikely it is that B-SAD are to survive; only two result combinations will lead to them escaping the automatic drop zone, not only required to win, but also needing Tondela to suffer defeat and Moreirense to drop points.

Meanwhile, the situation is much better for Tondela, who know that victory will see them remain in 16th place. They also know that any dropped points will open the door for Moreirense though, who will leapfrog them in the table with a victory should Tondela draw or lose to Boavista.

For Moreirense, this is exactly what they are relying on - though do also know that a draw could be enough should Tondela lose and B-SAD fail to win.