The formidable German pair, who are also the reigning Olympic and world champions, beat Joy Stubbe and Jolien Sinnema of The Netherlands in straight sets to reach the last eight.

Ludwig and Walkenhorst, seeded seventh at the tournament in the Latvian city, were in commanding form once again as they cruised to a 22-20, 21-15 victory over the 14th seeds.

Their opponents in the quarter-finals will be compatriots Julia Grossner and Nadja Glenzke after they overcame team-mates Margareta Kozuch and Karla Borger, the second seeds, 21-23, 21-15, 17-15 in a match that lasted five minutes shy of an hour.

Top seeds Julia Sude and Chantal Laboureur, also of Germany, booked their quarter-final spot with a comfortable 21-12, 21-17 win against the Dutch team of Madelein Meppelink and Sophie van Gestel in their last 16 clash.

Anouk Vergé-Dépré and Joana Heidrich of Switzerland, the tournament's third seeds, were unable to follow suit as they crashed out of the competition.

The Swiss pair were beaten 26-24, 21-15 by Ekaterina Birlova and Nadezda Makroguzova of Russia, who will go up against Poland's Kinga Kolosinska and Jagoda Gruszczynska for a place in the semi-finals.

In the men's tournament, Dries Koekelkoren and Tom van Walle of Belgium sealed their semi-final spot with a battling 18-21, 21-15, 17-15 triumph against Alex Ranghieri and Adrian Ignacio Carambula of Italy.

The Belgians will face Latvia's Aleksandrs Samoilovs and Janis Smedins, who delighted the home crowd with a 21-14, 21-17 triumph against Grzegorz Fijalek and Michal Bryl of Poland.

Defending champions Paolo Nicolai and Daniele Lupo of Italy safely reached the last eight as they beat Austria's Tobias Winter and Robin Seidl 21-17, 21-17.

The Italians will clash with Norwegian duo Anders Berntsen Mol and Christian Sandlie Sørum tomorrow, with the winner claiming a place in the semi-finals.