This week, tickets for the NFL's third competitive game at Wembley have sold more quickly than the previous two, with 20,000 snapped up in the first seven minutes.
"It is proof of a growing audience for the sport," said NFL UK managing director Alistair Kirkwood.
"We have been delighted with the way fans have got behind the game, especially considering the challenging economic climate."
The initial 70,000 allocation for the 25 October clash between New England and Tampa Bay has gone and another batch is only available until after Sunday's Super Bowl XLIII.
UK gridiron chief happy with progress
In October 2007, the NFL staged its first regular-season game outside the Americas, with 81,176 fans at Wembley watching the New York Giants beat the Miami Dolphins 13-10 before going on to win Super Bowl XLI.
Last year, the New Orleans Saints were 37-32 winners in a thrilling meeting in London with the San Diego Chargers, watched by 83,226.
The NFL has also staged games in Mexico City and Toronto over the last few years and said it is all part of a bigger plan to ensure planning is correct and that fans respond positively.
"We plan rigorously. There is a view for the future. We've taken a west coast team [to London] this year in San Diego and we've proved the logistics of that work," he explained.
"This year we're going to have games going on in London and Toronto at the same time so we definitely have a way forward."
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