Co-owner David Gold admits West Ham would have been in big financial trouble had they failed to make an immediate return to the Barclays Premier League.
Gold reckons Ricardo Vaz Te's goal three minutes from time to seal a 2-1 victory over Blackpool in the npower Championship play-off final at Wembley on Saturday has saved the debt-ridden club around STG50 million ($A80.7 million).
However, Gold is still prepared for a summer of spending as he believes manager Sam Allardyce will need around STG20 million investing in his squad to keep the Hammers up next season.
"Had we not won, it would have meant the owners would have had to find more money. It is painful. If you own 150 oil wells then it is no problem, but if you own 150 Ann Summers shops..." said Gold.
"It is hard to put it into financial terms because the first thing we would have done on Monday if we didn't win was say we need to cut our cloth accordingly.
"We wouldn't have sat there deluding ourselves, we would have needed to find more money. It would have cost around another STG30 million.
"It also depends on what you want to do. Do you want to challenge again in the Championship? If so you would have to find about another STG20 million.
"But I think we still have to do that, there is still hard work ahead. I still think the club has got to find STG20 million to ensure it doesn't get relegated again - and that is on top of the TV money.
"We obviously need to strengthen some areas and although I would expect significant changes, it won't be anything like last summer, when 26 players went and 19 came in.
"The hard work starts now. This club has debts we inherited. We are committed to paying these debts. The best way to put it is that we would not have bought West Ham if we weren't supporters - we would have to be mad."
Another challenge facing West Ham following their return to the Premier League is trying to keep goalkeeper Rob Green at the club.
Green, named in England's Euro 2012 squad last week, is out of contract this summer and was certain to leave Upton Park had the Hammers stayed in the Championship.
However, the play-off final win over Blackpool changes the equation, and Gold believes there is now a good chance of the 32-year-old staying.
"The offer we could have made to Rob would obviously not have met his requirements if we had still been in the Championship," said Gold.
"But now there will be one on the table which should be acceptable and hopefully we will wrap that up in the next five weeks."