The American softballers will play Japanese at the final on Thursday, which is the third encounter of both ace teams at the Beijing Olympics.
The American team, with an all-success record, pounded the Japanese 4-1 after two tiring extra innings on Wednesday morning.
Japanese softballers could have booked an early ticket to the finals with their solid defence, but the outstanding pitcher Ueno Yokiko, who hurled during all the innings at a speed above 110 kilometers per hour, failed to block the attack of the United States in the ninth inning, or the second of the tie-breaker, after a 0-0 stalement during the seven normal innings.
Caitlin Lowe's single hit brought the speedy Natasha Watley home with the game's first run. Designated player Crystl Bustos then secured the victory. Seeing two teammates on bases, the slugger sent a knee-height pitch from previously untouchable Ueno soaring up into the left field stands to bring home three more runs.
Japan's desperate batters tried to rally in the bottom of the ninth. Sachiko Ito hit a ground ball into the center field to drove Fujimoto home and score the sole run of the game.
"I set her (Ueno) to pitch all the innings in order to stop the USA scoring. But Bustos is a wonderful batter and we need to find a way to counter her if we could reach the finals tomorrow," said Japan's coach Haruka Saito.
In the following match between Australia and Canada, the Aussies subdued the latter 5-3 to have a do-or-die clash with the Japanese for a last chance to the final.
Watched by Jacques Rogge, President of the International Olympic Committee, and former president Juan Samaranch, the seesaw battle was proved a the most lengthy one at this Olympics, which lasted three and a half hours.
The boyish Ueno Yokiko again played throughout the epic match.
In the first inning, Australian Stacey Porter broke the ice by scoring one point at Sandy Lewis' batting.
But advantage of the Oceanian team was just saved to the fourth inning, as a homer by Japan's Hirose Megu sent herself and her teammate Mabuchi Satoko to the home plate. The score was changed to 1-2.