STANFORD, Calif. — Garbine Muguruza appears to be relishing her role as spoiler.  The 28th-ranked Spaniard, who shocked Serena Williams earlier this year on the terre battue of Roland Garros, pulled off another upset on Tuesday, this time taking out defending champion and No. 6 seed Dominika Cibulkova 6-2, 4-6, 6-2 at the Bank of the West Classic.     

The 20-year-old, who was making her tournament debut in Stanford, asserted herself early in a match in which she showed impressive power from the baseline.  While both players struggled from the service stripe with 10 double faults apiece, Muguruza out-aced her Slovakian foe 8-1 in securing the win in just under two hours.

“When you play another girl whose ranking is better, you don’t feel pressure. You just go out there and do your best,” said Muguruza, who also stunned Caroline Wozniacki en route to the fourth round of the Australian Open in January.

“It gives you confidence when you see that you can beat important players,” she continued.  “You see that you’re not far from them.  If you win these kinds of matches, you become more confident and believe more in yourself.”

Despite her 6-2, 6-2 win over Williams in Paris — the fewest games the world No. 1 has ever won in any Grand Slam match — Muguruza says she’s still the same player she was before upsetting her childhood idol.

“I don’t feel that I’m different,” he said.  “Every time I see that I’m closer, but I don’t see any difference.  I just have to improve more and lose more of the respect [for my opponent].”

Muguruza, the daughter of a Spanish father and a Venezuelan mother, is essentially a woman without a country. Although she currently plays under the Spanish flag, she won’t decide until later this year which country she will permanently call home.

“It’s strange, the moment I’m in right now, because I have half of my family in Spain, and half in Venezuela.  So it’s a tough decision.  I just want to have all the time that I need to decide, because it’s going to change my calendar, the tournaments and everything.  I’m just trying to let the time pass.  One day I’ll wake up and say, ‘Okay, this is what I have to do.’  I actually don’t know right now.  It’s difficult.”

She says both national federations have helped her career, but her ultimate allegiance will most likely come down to a family decision.

Muguruza will face the winner of the Paula Ormaechea-Daniela Hantuchova matchup in the second round.

(Photo: Getty Images)