After Jozy Altidore had given the US a first-half lead, Dempsey wrapped up a 2-0 triumph with a second goal 16 minutes from time as Bob Bradley's side became the first team to beat Spain sine November 2006. That unbeaten run had seen Spain draw level with Brazil's world record of 35 successive matches without defeat, while Vicente del Bosque's side had also won their previous 15 games on the trot to establish a new record.
"This win is huge for American soccer because it's the first time for the men to be in a final in a major competition," said Dempsey. America's triumph last night in Bloemfontein is even more remarkable considering they looked on their way out of the tournament after losing their opening two matches against Italy (3-1) and Brazil (3-0).
That left them on the brink of bidding farewell, but they managed to upset the odds and sneaked through in second spot in Group B after beating Egypt 3-0 on Sunday and seeing Italy lose be the same scoreline against Brazil. Those two results meant the USA pipped Italy to a place in the last four thanks to having scored one more goal than the world champions.
"This one is much sweeter because we were down and out, came back fighting in the Egypt game," added Dempsey on the official US Soccer website. "No-one expected us to win this game. We fought hard, showed a lot of heart, stayed compact defensively, picked our moments when to go forward and scored some goals and that made it difficult on them. I'm excited about the result, and think all the fans back at home will be excited as well."
Now the US will meet the winner of tonight's other semi-final between Brazil and hosts South Africa in Sunday's final, with Dempsey saying: "We realise there's another game to be played and if we meet South Africa or Brazil, it will be a tough game. We're looking forward to it."
USA captain Carlos Bocanegra has urged his side to try and produce these sorts of performances more often. "It just shows that we can compete with the best. Now we need to do it on a consistent basis, and that's the biggest thing moving forward," he said. "We've been a bit inconsistent, especially in CONCACAF, which we need to improve on. Coming here we've shown that we can play with the big boys and we can beat them."