The Seasiders take on Bolton at Bloomfield Road on Saturday, the penultimate fixture in what has been a remarkable Barclays Premier League campaign for Ian Holloway's side following their surprise promotion via the Championship play-offs a year ago.
Staying up would arguably be an even more notable achievement, although having continued to upset the odds for much of this season, a run of only one win in their past 16 matches has seen Blackpool slide into the relegation zone and they are currently a point adrift of safety.
They face a trip to champions-elect Manchester United in their final game and Tangerines midfielder Southern feels the team need to take maximum points from the Bolton contest if they are to have any chance of getting themselves out of trouble.
"They are two massive games and Saturday's is probably going to be the biggest in the club's history I would have thought," Southern told www.blackpoolfc.co.uk. "It will be bigger than (the play-off final at) Wembley and bigger than anything we have experienced, certainly in the last few years.
"It is must-win - I don't think a point will be any good to us really. We'll hopefully get the three points and then go to Manchester United on the last day, where anything you get is a bonus really."
Source: PA
Source: PA