Updated

One more for gold. One more before goodbye.

Pushed to extra innings, the U.S. Olympic softball team scored four runs in the ninth inning and beat Japan 4-1 on Wednesday to move within one win of its fourth straight gold medal — in the sport's farewell for now.

Crystl Bustos hit a three-run homer — almost out of Fengtai Field — in the ninth inning as the Americans extended their Olympic winning streak to 22.

On a hazy, hot and humid morning, the U.S. team had to sweat like never before in this tournament.

Blanked for eight innings by Yukiko Ueno, the Americans (8-0) got an RBI single from Caitlin Lowe in the ninth before Bustos put it out reach to get the U.S. into softball's last gold-medal game until at least 2016.

"That was softball at its best," U.S. coach Mike Candrea said. "Great pitching, great defense, some great adjustments at the plate. The international tiebreaker. The 20-second pitch clock. You saw a little bit of what the sport has to offer."

Tied after seven, the teams went to the international tiebreaker in the eighth as both began their at-bats with a runner at second base. Neither could score in the eighth, and they went to the ninth knotted.

The U.S. team started the inning with Natasha Watley on second and she scored when Lowe bounced a single off Japan shortstop Rei Nishiyama's glove and into center field, sending the American pouring out of the dugout in relief and celebration.

Jessica Mendoza walked and despite having first base open, Japan decided to pitch to Bustos, softball's greatest power hitter.

She made them pay when Ueno tried to overpower the American cleanup hitter, who connected for her fifth homer of these games and the 13th of her three-Olympic career — a blast to left that landed about five rows from the top of the 10,000-seat stadium.

"I was waiting for that pitch," Bustos said. "I knew she was going to come with it. I just wanted to get my bat on it."

Bustos smiled as she was asked to describe the feeling of driving a ball that far.

"You don't even feel it," she said. "Like I was telling coach, you don't even feel it hit the bat. You just feel the motions before it, but you don't feel it, you just see it."

Standing at second, Lowe watched as another Bustos' blast soared over the wall.

"So cool," Lowe said. "I felt like I was doing the home-run trot around the bases. When she gets a hold of one, you know it's out. It was a great kind of exclamation point on the day."

Monica Abbott pitched eight shutout innings for the U.S., which could face Japan again for gold Thursday. The Japanese will play the Australia-Canada semifinal winner later in the bronze-medal game with the winner meeting the Americans.

For eight innings, the zeros on the center-field scoreboard nearly outnumbered the Olympic logos ringing the ballpark's outfield wall.

Ueno and Abbott were going pitch for pitch, out for out in the tournament's best game by far.

Before the game moved to extras, the U.S. had its best scoring threat in the sixth when Tairia Flowers singled leading off, and Lowe was awarded first base with one out when Ueno didn't get her 3-2 pitch off in the required 20 seconds.

But Mendoza, who came in batting .421 with four homers, lined out to third baseman Megu Hirose, who snapped a throw to first and doubled off Lowe.

Behind Abbott, the U.S. team had beaten Japan 7-0 in round-robin play, needing just five innings to discard the defending bronze medalist before the game was halted by the international run-rule — one of five walkovers by the Americans in the preliminaries.

But with so much at stake this matchup figured to be different, and was it ever. It was the toughest test yet for the Americans, who have outscored the field 57-2.