LONDON -- Monica Puig has fallen in love with the All England Club, yet the 19-year-old player from Puerto Rico refused to be overawed on court at Wimbledon on Monday.

Playing in her first grass court tournament as a professional, Puig produced the first upset this year, defeating the fifth-seeded Sara Errani 6-3, 6-2.

Puig made her Grand Slam debut this year at the French Open, where she became the first woman from Puerto Rico to reach the third round.

"I just think it's so elegant," Puig said about Wimbledon, where she had not played since 2010, when she was still a junior. "All the green courts with the white, it's so special. It's the only Grand Slam that does that, so it's just a wonderful tournament."

Despite her lack of experience. the 65th-ranked Puig wasn't overawed by the occasion. Serving hard and making just a few mistakes, she gave the French Open semifinalist a lesson of aggressive tennis before closing out the match with her 38th winner.

Puig said her good run of form at the French Open, added to a difficult defeat earlier this year, helped her to be more confident at key moments.

"Mentally, physically it just all comes together," she said. "Before this year, I had a really tough loss to (Angelique) Kerber in Brisbane and wasn't able to close that one out. But obviously losing that match was probably one of the best lessons for me because I ended up learning from it and closed off some pretty big matches."

Puig moved to Miami as a child because of her dad's business. She grew up admiring former Wimbledon semifinalist Gigi Fernandez of Puerto Rico as well as Jennifer Capriati, and then Serena Williams. She said she is also drawing some inspiration from the men's game.

"Serena is starting to become the most consistent player, in my opinion, on the tour, so obviously I try to use her as an example on the court, the way she conducts herself and just the aura that she brings onto the court," she said. "She intimidates the opponents, and she is just able to maintain that level through the whole match. That's something that men do very well, and I think they've had a lot of success doing that. So I just try and take a little bit of both the men's and women's tour."

Puig's recent results have not been unnoticed in Puerto Rico, a country where tennis is not the most popular of sports.

"Yeah basically," she answered, laughing, when asked if she was now a national hero. "The big sports over there are basically boxing, baseball, and basketball. Now that I've been doing well, tennis is starting to become bigger as well."

Errani, who had reached the semifinals or better at three of the last five Grand Slams, withdrew from last week's grass-court warm-up at Eastbourne with a leg injury. She did not try to make excuses after her loss to Puig, saying she did not play before Wimbledon more as a precautionary measure.

Errani, who slipped a few times on the court, said she needs to improve the way she moves on grass to stand a chance at the grass-court Grand Slam in the future.

"My biggest problem is movement, in the sense that I'm worried I'm going to hurt myself," she said. "I'm afraid to run. And I don't have strokes that can hurt an opponent on the grass. I don't think I played disastrously. But she played better."