Spain were expecting to face Italy or Egypt in their Confederations Cup semi-final this evening but instead the US stands between them and another world record.
The unlikely outcome materialised after Brazil beat Italy 3-0 and the United States upset Egypt by the same margin on Sunday, with Bob Bradley's team going through on goal difference.
Despite having to revise his plans, Spain coach Vicente del Bosque said the US deserved to qualify.
"They had Italy against the ropes and heavily beat Egypt, who were until then the revelation of the tournament," he said.
"They are fast, well organised, and they will come into the match with plenty of desire."
Nevertheless, the odds are heavily stacked against a team who have the unenviable task of trying to become the first side to beat the European champions since November 2006.
If Spain avoid defeat, they will eclipse Brazil's 35-match unbeaten run, set between 1993 and 1996, to rewrite the history books for the second time in less than a week.
By beating South Africa over the weekend, they stretched their winning streak to 15 games, something no other national team has achieved.
While Del Bosque admits records are a motivating factor, there is more at stake than that with a place in Sunday's final in Johannesburg against Brazil or hosts South Africa the reward for winning.
There are few weak points for the US to exploit, with Fernando Torres and David Villa a formidable proposition for any defence.
Torres scored a hat-trick in Spain's 5-0 demolition of New Zealand while Villa has put aside personal distractions regarding his on-off move away from Valencia to score in all three of Spain's matches so far.
Add into the mix players like Xavi, Cesc Fabregas, Xabi Alonso, and Carles Puyol and it is a titanic task.
Torres said the side, which has yet to concede a goal, was driven by setting records and winning their first FIFA trophy.
"Everyone will remember this team in the future and when we look back on it we will be even prouder," the Liverpool striker said about their record-breaking run.
"But we don't want to stop here. We want to play the final and win it. We are ambitious and we are hungry."
Bradley is no dreamer and knows it will need something extraordinary to prevail tonight, particularly with Spain having an extra day to rest and prepare.
"Spain are a great team," he said.
"We played them last year in a friendly in Santander, their last warm-up before Euro 2008.
"They wore us down in the second half, but then we watched as they wore down Russia, Holland and eventually Germany at the European championships.
"I pointed out to the players that they should take note that we had done a good job.
"It's a short turnaround and playing them is such a challenge, it's like playing Barcelona and the national team. We'll have our work cut out against the likes of Torres and Xavi."