The new Wembley Stadium will be a "truly special" venue to be proud of, even if it opens later than planned, its chief architect says.
Builders Multiplex admitted last month there was only a 70% chance the stadium would host the FA Cup final on 13 May.
But Lord Foster said critics should not have a field day if that happened.
"Would it be the end of the world if it wasn't completed in time for that? In the long-term, this building is going to be around for many, many years."
Lord Foster spoke to the BBC News website as he recorded an audio slideshow explaining his original designs for the 90,000-seater stadium - which is due to be English football's new home, as well as London's premier concert venue.
The designs have since been buried in a time capsule under the pitch of the new stadium.
In the recording, Lord Foster outlines the challenge he and Wembley's design team faced in finding a suitable landmark to replace the famous Twin Towers of the old stadium, which were demolished despite a public campaign to save them after the old stadium hosted its final match in 2000.
Lord Foster's firm, Foster and Partners, has been behind some of the most distinctive buildings in the world, including the Shanghai Bank in Hong Kong (then the most expensive building ever), Berlin's Reichstag, the Greater London Authority's "glass egg" headquarters and the Swiss Re skyscraper in London, which is affectionately known as "the gherkin".
For the Wembley project, the firm joined forces with HOK Sport, a Kansas City-based firm which has designed many of the world's leading sports stadiums, including Cardiff's Millennium Stadium and Arsenal's new home at Ashburton Grove.
Instead of Twin Towers, it was deemed the new Wembley should be known for its arch. Since it was raised into position in 2004, it has become a distinctive new landmark on the west London skyline and one which the award-laden architect hopes will be taken to the public's hearts in a similar way.
He said fans going to evening matches would see the arch fully illuminated as they entered the stadium.
He predicted: "The arch will become not just something which is specific to that part of London or indeed London as a city but it will be a global image which is unique and special to Wembley."
The 70-year-old also explained why it was decided not to have a permanent athletic track at the stadium.
"That's because the challenge is to give the spectators more space, 30% more than in the original Wembley, but to also get them to feel closer - physically and emotionally closer - to the action and to encourage, to recreate the drama of the old Wembley, its intimacy with the roar."
FACTS ABOUT NEW WEMBLEY
The Wembley Arch is 133m high, taller than the London Eye
It weighs 1,650 tonnes and supports the 7,000-tonne roof
On a clear evening, it can be seen from Canary Wharf, 13 miles away
It is made of British steel, supplied by Corus
It was initially worked on in Cleveland then transported south to be joined together
The stadium will have 2,000 toilets - more than any other building in the world
The 11-acre roof makes it the biggest stadium in the world with every seat under cover
The total project cost was put at £757m - when work began
The two giant screens are each the size of 60 standard TVs
The legroom for each seat is more than in the old Royal Box
Lord Foster insisted he had not been disheartened by reports which have focused on the growing projected cost of the project and the danger that it may not be ready on time.
He said: "A project such as this is high in the public profile so perhaps not surprisingly this has to be one of the most audited projects that's ever happened. Inevitably along the way it's been subject to criticism.
"It's the race to completion right now. If it wasn't completed in time, there would be enormous disappointment, but in the longer-term scheme of things, this building is going to be around for many, many years.
"It's going to go way into the future so in the bigger perspective, that [the opening being delayed] would be a blip.
"Right now this year, it would be a very disappointing blip."
But when it does open, the architect, who says he enjoys big football matches without feeling an allegiance to any particular team, wants the public to judge whether it is a success.
"The final acid test is when you have those epic matches and you feel the intimacy of that big bowl and you feel the action.
"We're going to have something the likes of which has never been seen before. Never has something on this scale been attempted with the range, diversity and depth of other facilities, with the convenience, with the quality that's embodied in this project.
"We're all really proud to have played a part in its transformation, in its rebirth, in its renaissance."
A Wembley Stadium spokeswoman insisted there was no change in the assessment that Wembley was 70% likely to be ready to host the FA Cup final.
She also paid tribute to Lord Foster for the role he played in the team that designed the stadium, saying: "The greatest stadium in the world required the best architects in the business and this was delivered by World Stadium Team, a partnership between Foster and Partners and HOK Sport.
"Both are high profile, internationally renowned architects with a proven track record for ground-breaking and inspirational design.
"The design of the Stadium bowl itself gives all spectators fantastic and unobstructed views of the action and an unrivalled experience on event day and the arch has quickly become a new landmark for London and an iconic symbol for world sport."