Finsters and Tocs fought to a 17-17 tie in the first set of their second-round qualification match against the 2014 silver medallists.

They then went on to seal the first set 21-19 and eased past the Spaniards 21-13 in the second.

"They were fighting till the end," said Tocs.

"We were a little bit lucky on the net, in the blocking and attacks.

"They struggled a little bit in the second set and we pushed it to the end.

"We have done things we have to do - it was good."

Top seeded qualifiers Philip Gabathuler and Mirco Gerson of Switzerland and six other tandems also clinched their berths in the main draw.

Gabathuler and Gerson swept Germany’s Armin Dollinger and Lorenz Schumann 21-14, 21-16 to advance into the main draw.

The German pair cut their deficit to 17-14 in the second set thanks to a brilliant block by Dollinger, forcing Gabathuler and Gerson to call a time-out.

But after the game resumed, the Swiss duo regained their edge and wrapped up the match in 35 minutes.

The other teams advancing to the main draw are Austria’s Thomas Kunert and Christoph Dressler, Russia’s Nikita Liamin and Dmitri Barsouk, Australia’s Cole Durant and Bo Soderberg, Poland’s Michal Bryl and Kacper Kujawiak, Norway’s Morten Kvamsdal and Sandlie Sørum, and Serbia’s Stefan Basta and Lazar Kolaric.

Croatia’s Silic Filip and Ivan Zeljkovic withdrew from their second-round match against Kunert and Dressler due to a knee injury that Zeljkovic incurred in the second set.

Among the 24 teams awaiting in the main draw are Latvia’s Aleksandrs and Janis Smedins, who finished third in Xiamen last year, and Italy’s Paolo Nicolai and Daniele Lupo, the 2014 Fuzhou Open winners. 

The 32 remaining teams will play in eight round-robin groups with the top two finishers from each making the last 16.

The event continues the road to Rio 2016 that lasts until June 13.

The FIVB World Tour events count towards the Olympic ranking, which will determine 15 of 24 spots for each gender that will take part in this summer's Olympic Games.