Samantha Stosur has stormed into the Gastein Ladies quarterfinals by beating Klara Koukalova of the Czech Republic 6-1, 6-0, while top-seeded Sara Errani and No. 7 Anna Karolina Schmiedlova won their first-round matches.

Stosur, the second-seeded Australian, saved three break points in the opening set. She dominated the second, but double-faulted on match point twice before closing out the win in 49 minutes.

In her first quarterfinal since winning her seventh career title in Strasbourg in May, Stosur will play Danka Kovinic of Montenegro, who defeated lucky loser Richel Hogenkamp of the Netherlands 6-3, 6-1.

Polona Hercog of Slovenia also reached the quarters by ousting fifth-seeded Lucie Hradecka of the Czech Republic 6-3, 6-2.

In first-round play, Errani sweated to get past Aliaksandra Sasnovich of Belarus 6-4, 6-4. The 19th-ranked Italian dropped serve three times and held off eight more break points.

Schmiedlova, who beat Errani in the final at Bucharest last Sunday, overcame a slow start to defeat Patricia Mayr-Achleitner of Austria 3-6, 6-2, 6-0. The Slovakian was broken twice in the opening set but won nine straight games from 3-2 in the second set.

Suffering from persistent back problems, 2011 finalist Mayr-Achleitner said after the match she will retire from competitive tennis at the end of the season.

In the only other remaining first-round match, Johanna Larsson of Sweden downed Stefanie Voegele of Switzerland 6-2, 6-2.