SAN JOSE, CA, USA -- No.5 seed Mihaela Buzarnescu of Romania slid into her seventh WTA quarterfinal of the season at the Mubadala Silicon Valley Classic on Thursday, moving past 16-year-old American qualifier Amanda Anisimova, 7-5, 2-6, 6-1, in the second round.

"It was not an easy match because she’s such a young player," Buzarnescu told the media, after the match. "She’s from the new generation, and I’m from the old one, and I knew the pressure would be on me because she has nothing to lose."

Buzarnescu came back from a 5-3 deficit in the opening set, then survived a thunderous second-set comeback by Anisimova, easing past the teenager in one hour and 46 minutes, in their first meeting. The consistent Buzarnescu has now won her last 26 matches against players ranked outside the Top 100.

"It was an up-and-down match and I was coming back in the first set, leading in the second set, and then with some easy mistakes, she came back and she had more confidence," Buzarnescu explained. "Then in the third set, I really managed to play well, and play my own game."

The 30-year-old Romanian, ranked World No.24, finished the encounter against her young foe with 26 winners, eight more than Anisimova. Anisimova, the reigning US Open junior singles champion, who turns 17 next month, impressed during the second set, but was undone by 46 unforced errors during the match as a whole.

Buzarnescu now moves into the final eight, where she will face either Australia's Ajla Tomljanovic or lucky loser Magdalena Frech of Poland. Frech replaced second-seeded American Madison Keys, the defending champion, who withdrew from the tournament on Thursday due to a right wrist injury.

"Whoever the winner is, it’s not going to be an easy match," said Buzarnescu. "I just want to do my own game against whoever I play, and just try my best."

The players exchanged breaks twice en route to 4-3, before an error-prone Buzarnescu gave up what seemed to be a crucial break in that game. This put Anisimova up a break for the second time in the set, and allowed the American to serve for a one-set lead at 5-3.

But Anisimova was unable to take advantage, as Buzarnescu tightened up her service returns, and the Romanian lefty broke the teenager again to get back on serve at 5-4, after Anisimova ended a rally with a long backhand miscue.

This kicked off a run of four straight games for Buzarnescu, as the Romanian found her targets more frequently while Anisimova’s errors mounted. Buzarnescu won 12 of the last 14 points to blow through the remainder of the set; Buzarnescu had 11 winners to Anisimova’s nine, while the young American had 19 unforced errors, two more than Buzarnescu.

Buzarnescu dominated the early stages of the second set, breaking Anisimova at love and then consolidating for 2-0 with a love hold. After the Romanian picked up the first point on Anisimova’s serve in the next game, she had won 15 straight points and seemed queued up for a breezy victory.

But Anisimova started to play with greater depth and consistency, and out of nowhere, Buzarnescu started piling up errors. The American got out of that game with a hold for 2-1, ending Buzarnescu’s six-game winning streak. Suddenly, Anisimova started racking up games, breaking back for 2-2, and garnering a second break for a 4-2 lead.

The teenager blasted forehand winners with ease to hold for 5-2, and Buzarnescu faltered once more on her serve in that game, allowing Anisimova an amazing six-game streak of her own to close out the second set from behind.

But Buzarnescu regrouped solidly in the decider, breaking Anisimova at love to start the third set, and whacking a backhand winner on break point two games later to take a 3-0 lead. The Romanian staved off a break point with a strong serve en route to a hold for 4-0, putting her within touching distance of her 32nd main-draw victory of the season.

Anisimova demonstrated her mettle by fending off four break points in the next game and holding for 4-1, but Buzarnescu was unstoppable in the final set, closing out the match two games later by breaking the American teen with one final backhand winner.