Fourth seed Teliana Pereira continued to fly the locals' flag high at the Brasil Tennis Cup, advancing to the semi-finals on Thursday.

Pereira downed Laura Siegemund 6-3 7-5 in their quarter-final of the WTA International clay-court event in Florianopolis, although it was more of a struggle for the Brazilian than the scoreline suggests.

The world number 78 skipped to a 4-0 lead, but Siegemund had saved six-of-eight break points at that stage as the German battled and eventually conceded service games.

One immediate break back was not enough, as Pereira took the first set - but Siegemund was on track to send the match to a decider when taking a 3-1 lead in the second.

However, Siegemund - ranked 128th and seeded seventh - was broken twice in succession as Pereira moved within two games of advancing to the tournament's semi-final stage for the first time.

Pereira had previously reached the semi-finals of a tournament in Brazil - in Rio de Janeiro in 2014 - but nerves still got to the 27-year-old, as she was broken back for 4-4.

She faced two set points on her serve in the 10th game, but Siegemund's failure to take them was costly - as Pereira broke, and held, to 30 to seal the win in one hour, 56 minutes.

Awaiting Pereira in the semi-finals is Latvia's Anastasija Sevastova, who was too good for Maria-Teresa Torro-Flor 7-6 (7-4) 6-4.

Sevastova, who previously climbed as high as 36 in the rankings but is now 188th, is one win away from just her second WTA Tour final, having won the Portugal title in 2010.

In the other semi-final, third seed Annika Beck and fifth seed Bethanie Mattek-Sands will go head-to-head.

Germany's Beck ousted Brazil's Gabriela Ce 6-3 6-3, while Mattek-Sands endured more of a struggle against Tereza Martincova before saluting 7-6 (7-2) 4-6 6-1.

Both Mattek-Sands and Martincova broke thrice in the opening set, and six of nine points went against serve in the tie-break before the American won it.

Mattek-Sands was on the brink of victory with a 4-3 break lead in the second, before Martincova reeled off three straight games - and two breaks - to force a decider.

But the Czech's momentum was lost immediately in the third, dropping serve all four times in the set as Mattek-Sands survived.