Barbora Strycova is through to the quarter-finals of the Ladies Open Biel Bienne after being made to work hard in her second-round match with Carina Witthoeft.

The Czech top seed came through 6-2 7-6 (7-6) against her German opponent, triumphing after failing to serve out the match at 5-4 in the second and seeing one match point go begging in the tie-break.

"I felt great on the court, serving for the match at 5-4. I didn't make it there, but Carina was playing amazing tennis and it was a tough game for me with all the long rallies," Strycova told WTA Insider. "I'm happy I made it through because the tie-break was on and off. My serve was also working well in the end."

Carla Suarez Navarro is out, however, the second seed undone by a Camila Giorgi comeback. Giorgi recovered from a set down to win 2-6 7-6 (7-5) 6-2.

Elsewhere in the draw there were straight sets wins for Aliaksandra Sasnovich and Marketa Vondrousova.