RIO DE JANEIRO (AP) — So stung by a devastating defeat to Brazil in the championship match of the London Games four years ago, silver medalists Foluke Akinradewo and Jordan Larson contemplated walking away for good from the U.S. national team and skipping another Olympic cycle.

One by one, something slowly pulled each woman back to join new coach Karch Kiraly and support his plan for Rio de Janeiro.

"I took the summer off for the most part to re-evaluate and make sure I still loved the game, and I did, so I came back," Akinradewo said, "and I'm really happy I did."

Despite the deep sense of hurt after failing as the undeniable favorites, she and Larson knew one thing: They had to go for it again and chase that gold medal they knew was oh-so-close before calling it a career.

And everybody involved realizes how much these two mean for the top-ranked and unbeaten Americans (6-0) in Brazil. They helped lead the U.S. one step closer to the goal and reach Thursday's Olympic semifinals with a straight-set victory against Japan on Tuesday. The Americans will play Serbia, which beat Russia later Tuesday.

"That's awesome, that's been our goal," said Akinradewo, who provided the winning kill on match point to cap the 25-16, 25-23, 25-22 victory. "That's why we're here."

The hard-hitting, high-flying Akinradewo is a menacing force at the net — "She gets kills in her sleep," teammate Kim Hill said. The businesslike, reliable Larson is a steady presence in the lineup match after match.

"They're a part of building and laying the foundation for the culture that we've created," captain Christa Dietzen said.

By late summer of 2013, Akinradewo had undergone shoulder surgery and would stop by the team's Orange County headquarters about once a week to check in, work out and just say hello. Larson, too, by then had decided to give it another chance, eager to follow Kiraly's lead.

That part was easy.

"I was pretty sad with how London ended and just whether I wanted to continue my career at all. That's where I was at and I liked what Karch was doing and what the girls were trying to do," Larson recalled. "I really wanted to be a part of that. I thought it was going to be a cool thing."

Akinradewo is 28 and Larson 29. Both have aspirations beyond volleyball. Yet those goals can wait for at least another week.

"I love that our players are just all in giving it another shot here," Kiraly said. "Ultimately they have to make their own decisions, so Jordan went through a process of pondering, mulling and weighing the options to play more and Foluke, too. She's just gnarly. She's like a thoroughbred, she's just such an unbelievable jumper and the quickness and the explosiveness that she has."

Aside from her pure athleticism, Akinradewo's playful nature has been a positive. She has a signature move she'll break into every so often called the "calf dance," including obliging teammate and setter Courtney Thompson on the 94th day counting down to Rio by taping a "9'' on one leg and "4'' on the other. Akinradewo does it "to show them off when she's not self-conscious" about her lower legs, Kiraly said.

"Those two, I can't say enough good things. It gives me chills thinking about it," Thompson said. "They get their team going. There's no better two that lead by example than Jordan and Foluke. Those two have a really powerful energy, and they set the tone."

Akinradewo, a former Stanford star, is thankful she decided to stick with it. She knows now that it would have been a mistake to walk away from this tight-knit group.

"If I would have retired from volleyball I would have been missing out on some great things," she said. "I'm just really honored and humbled to be part of this group, absolutely."

Larson has only one small request.

"I just wish she would give me some of her vertical," Larson said, "just a little bit."