American Claressa Shields fights for boxing gold

(CBS News) LONDON -- The United States has always been a power in Olympic boxing.

But this year, only one American has a chance at a gold medal, in the first Games in which female boxers have been allowed to compete.

The U.S. team's hopes are riding on Claressa Shields and her punishing uppercut.

She was to fight for the gold medal Thursday.

When fighting Claressa, it's her stamina that hits you before her gloves ever do.

At just 17, she boxed her way past the semi-finals and into the gold medal bout.

Now the teen from Flint, Mich., is just one fight away from being the middleweight Olympic champion.

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Her teammate, Marlen Esparza, lost in the semi-finals, but is still ensured a spot on the podium with bronze.

This is the first time female fighters have been allowed to box at the Olympics, and Shields could become America's inaugural title holder.

"That means a lot to me," she says. "It's not just about making history: I put in so much hard work. I would be very disappointed to go to London and not get a gold medal."

The milestone highlights what have become "the women's games" in London. On the U.S. team, women have gotten more than double the number of gold medals of men. And female boxing is expected to hit a new peak in popularity with its debut at the Olympics. For the better part of the 20th century, it was banned in most countries.

For Claressa, boxing is all about being disciplined. "You gotta be, or else this (is) not the sport for you. ... I train twice, three times a day," she says.

Claressa's dedication earned her a spot at the Games, but it was her dad's dream that got her in the ring. Claressa didn't meet him until she was 9 years old. Her father was in jail nearly her entire childhood.

"He couldn't really do nothing, there was nothing for him," she recalls. "He said his dream was to be a boxer. ... So when he said boxing was his passion, I decided I would box."

That started her career at the age of 11. She's only lost one match since. And she's beaten out her male counterparts as the youngest person to make the U.S. Olympic boxing team in 40 years.

Claressa's father once told her boxing was a man's sport, but it was only a reason to push harder/

"That was one of the big motivations for her to become a boxer," explains Chris Mannix, a writer for Sports Illustrated. "She figured anything a man can do, I can do, too."

Mannix says Shields has the straight punch of Sugar Ray Robinson, and the difficult back-story of other famed fighters. "Most boxers come from tough backgrounds," he points out. "They come from broken families. And Claressa Shields is one of them. ... And, like most male boxers, she's harnessed that atmosphere and been able to take herself to the top."

And Claressa isn't letting up.

She's spent her whole life being tough -- in and out of the ring -- and she's not about to pull any punches now.

Getting to fight for gold is everything Claressa's father ever dreamed of, but he won't be able to see that dream come true, in person, for his daughter: Because of his criminal record, he was unable to secure a passport to travel to London.