RIO DE JANEIRO (AP) — Monica Puig is trying to accomplish something no one from her country has ever done. Angelique Kerber is seeking to achieve the sort of thing she's already done this year.

They play each other Saturday for the Olympic gold medal in women's tennis. Puerto Rico's Puig, ranked 34th in the world, is the upstart in every way. Kerber, the Australian Open champion, is starting to look very comfortable in the role of favorite.

The 22-year-old Puig will become just the ninth athlete from Puerto Rico to win an Olympic medal in any sport — and if she beats a Grand Slam champion for the third time in four matches, she will be the island's first gold medalist.

Her underdog run to the final comes amid the economic crisis devastating the U.S. territory, which fields its own Olympic team. Puig is deeply aware of what her triumphs mean.

"This Olympics isn't about me. It's about Puerto Rico, and I know how bad they want this," she said. "The island is full of such bad news all the time so every time ... somebody from the island wins a medal, everything stops. I know how happy everybody gets."

Puig was so happy Friday after her back-and-forth 6-4, 1-6, 6-3 victory over two-time Wimbledon champion Petra Kvitova that her celebratory leap probably got enough hang time to earn points in the Olympic trampoline final. She dropped the first three games against the far more seasoned Czech, who's seeded 11th. Unfazed, Puig rallied to win the set, then regrouped again after taking just one game in the second.

Puig, who also upset French Open champion Garbine Muguruza in Rio de Janeiro, has never even been to a quarterfinal at a major. The 28-year-old Kerber has made two Grand Slam title matches in this breakthrough year.

The one in Melbourne in January was the first of her career, and the German lefty stunned Serena Williams in three sets for the championship. Then Kerber built on that success with her run at Wimbledon, where she lost to a nearly flawless Williams. She has a chance to overtake Williams for the No. 1 ranking this year.

"I have a lot more confidence than last year because I won one of the biggest tournaments," Kerber said, "and also because I had a lot of experience from past years."

That showed against 21-year-old American Madison Keys in Friday's second semifinal. Kerber saved all 10 break points she faced in a 6-3, 7-5 victory.

"She stepped up her game every time I had an opportunity," said the seventh-seeded Keys, who faces Kvitova on Saturday for bronze.

In the men's semifinals Saturday, 2012 gold medalist Andy Murray will play Kei Nishikori and 2008 champion Rafael Nadal will meet Juan Martin del Potro.

When Williams was upset in the third round of the women's tournament, the second-seeded Kerber became the favorite. She's looked the part, yet to drop a set through five rounds.

"She's really found her game," Keys said. "She's at the top right now."