Five teams go into the final day of the Premier League season knowing they are in danger of joining West Ham in the Championship next season.
In one of the closest relegation battles in Premier League history, Wigan and Blackpool occupy the other two places in the bottom three.
But the pair are on the same points total (39) as 17th-placed Birmingham.
Wolves and Blackburn have 40 points but know that any two of the five could still drop out of the top flight.
For Wigan and Blackpool, even victories in their final games may not be enough to save their Premier League status, depending on results elsewhere; paradoxically, they could lose and stay up.
Blackpool face the toughest task away at Premier League champions Manchester United, Birmingham are at Tottenham, Wigan travel to Stoke while the winner of the huge Wolves v Blackburn fixture will guarantee survival.
Blackpool boss Ian Holloway, who suggested that the Premier League wanted his side to go down, knows even becoming the first away team to win at Old Trafford this season may not be enough to keep the Tangerines in the top flight.
Asked how it would feel to be relegated, he said: "It will be the end of the world. It will definitely feel like that.
"You can't be a football manager, or a player, or have anything to do with a club and be happy if you go down. All you can do is let the dust settle and go on."
But Holloway remains bullish about getting a result at Old Trafford.
"I take great motivation from the way we played against them earlier this season. For 70 minutes we were absolutely magnificent," he said.
"Then they brought on Ryan Giggs and Javier Hernandez and we ran out of steam [and lost 3-2 at home].
"But this is an opportunity for us to achieve the best thing we could ever have dreamed of: keeping a club like ours at this level."
United boss Sir Alex Ferguson has vowed to pick a strong side for the match, despite having the Champions League final against Barcelona just a week away.
And another Old Trafford legend Paul Scholes has admitted he would be sorry to see Blackpool return to the Championship, if only for the absence of Holloway's unique appearances in front of the media.
"Ian Holloway's press conferences are brilliant," said Scholes.
"Listening to what he has to say is something to look forward to on a Friday afternoon.
"He has been great for Blackpool. The way they have approached the season is a breath of fresh air.
"They want to come out and score goals and even against us, I am sure they won't just try to sneak the odd goal and defend."
Wigan manager Roberto Martinez has given his players the obvious target of simply winning their game against Stoke before worrying about the many permutations.
"It's very simple, we need to be in a position where we can compete against Stoke, who are very strong at home, and we have to try to win," said the Spaniard.
Martinez's side kept their survival hopes alive with an injury-time winner against West Ham last Sunday that relegated the east London team and he is likening the game at Stoke as the club's second cup final in a week.
"To win the first cup final in the 94th minute, it gives you a real feeling of victory and of joy," Martinez told BBC Radio 5 live.
"It will be a phenomenal achievement to be successful in this campaign because in my eyes it has been one of the hardest seasons we have had in the Premier League."
Wolves boss Mick McCarthy insists that he is relishing the tension as his side head into the final day with their destiny still in their own hands.
"Am I enjoying it? I am enjoying it all," he said. "What is the alternative - to go and play golf?
"It is an absolutely fabulous job despite all the pressures and attention I get. I don't want to do anything else - I love it."
McCarthy believes that fellow relegation candidates Birmingham may not be tougher opponents than a mid-table side with far less at stake.
"It probably helps that it makes them as nervous as we will be," he added.
"I am never quite sure whether it is a good thing or a bad thing when you go into a game against a team that is relaxed and nothing to lose.
"Does it take the edge off their performance or does it give them an ability to relax with a bit of gay abandon?"
Birmingham manager Alex McLeish is refusing to be distracted ahead of facing Tottenham by speculation linking him with the vacant hot seat at West Ham.
"It's hypothetical stuff. I'm not going to get involved in ifs and buts [about my future]," said the Scot, who guided his team to Carling Cup glory earlier this season.
"But I do know [Sunday's game] is probably the biggest of my career. It is certainly the biggest of my managerial career - so bring it on.
"I believe we will stay up. We have to try and play to the strengths the players possess. We know opening up against a Spurs team could be deadly.
"We've got our own strategy and we have to try and be good on the day to get a positive result at White Hart Lane."
If Birmingham do end up going down, it would be a sad end to a season which had looked to be a success story after they beat Arsenal to win the Carling Cup in February, a result which means they will play in next season's Europa League.
"The Carling Cup win was fantastic and it's something we will never forget," said Birmingham's Craig Gardner, a lifelong Blues fan.
"To lift a trophy for the fans and the club after so long was fantastic.
"But this game is our career, it's bigger than the cup final and we need to go out there and give it every single ounce for this club.
"On a personal level this has been my first full season at Premier League level and it's been a great season for me. But I'd give up every single goal now just to stay in the league.
"In fact, I'd give my winner's medal back to stay in the league."
Blackburn manager Steve Kean said his team were in confident mood ahead of their trip to Wolves after picking up five points from their last three games.
Kean said: "Wolves have been quite animated - it's 'Beat Blackburn Weekend', it's 'Survival Sunday' down there - but we want to view it as 'Success Sunday' because we are in good form.
"It's not a case of us fearing going to Wolves, we are going into the game really looking forward to it and to have a really good ding-dong.
"We have been positive against Manchester City, Manchester United and West Ham and we are not going to sit back and play into their hands, and let them batter us with balls into the box."