I'm like a cola bottle going off, says giantkiller Puig

Puerto Rico's Monica Puig stunned French Open champion Garbine Muguruza to close on an Olympic medal, comparing her relief to a fizzy cola bottle being unscrewed.

The 22-year-old raced to a 6-1, 6-1 win over the third seeded Spaniard to make the quarter-finals where she will face Germany's Laura Siegemund.

Puig, the world number 34, fell to the ground in celebration after securing her famous victory.

"I still have goosebumps, it's like you are trying to keep it together. At 4-1, serving to consolidate that second break in the second set, you are so emotional," said Puig.

"You are getting close to winning, there's no hiding it. You start feeling those butterflies, those nerves.

"You keep it all bottled up. It's like a Coca-Cola bottle. If you shake it and shake it and shake it, it's going to explode.

"So I tried not to let it explode until the right moment."

Puerto Rico has only won eight Olympic medals, six of them in boxing.

The country has never claimed a gold medal with boxer Luis Ortiz in Los Angeles in 1984 and wrestler Jaime Espinal in London four years ago coming the closest with a silver apiece.

"It's the biggest win of my career, one of the most special as it is the Olympics. I'm really proud of the way I have been carrying myself at these Olympics," said Puig.

"It's sometimes hard not to get carried away with being here but I just wanted to keep my focus."

Puig started the year ranked at 92 in the world; now, she is on the cusp of the top 30.

She started 2016 by making a top-tier final in Sydney as a qualifier before losing to two-time Grand Slam winner Svetlana Kuznetsova.

But coming to Rio represents a new high for Puig.

"It's different because I am carrying my country's colours, while on the WTA Tour I am playing for myself. Here it's not my job, it's for Puerto Rico and nothing in the world can compare to this," she said.

"It's a most special feeling when you are walking around the Olympic village and people look to see what country is on the back of your shirt.

She added: "I hope my phone hasn't blown out by now. I think it might in the next few hours. But I love seeing all the support I get from my family and country.

"This is not for me; it's for them."

Muguruza has been in a slump since her maiden Grand Slam win in Paris in June.

She lost in the first round at Mallorca and Montreal and second round at Wimbledon.

But she refused to be despondent.

"I didn't find a way to beat her but I am over it. I have to go on the court for doubles later (with Carla Suarez Navarro)," she said.

"It's disappointing and frustrating to lose. It's my first Olympics. I wasn't expecting to come and get the gold medal

"I hope to keep going in that and the mixed (with Rafael Nadal) so I am not left with this bad taste."

Muguruza said she was optimistic she could change things around in the second half of the season.

"Tournaments after the French Open didn't go my way but the year is long and you never know what can happen."