The duo, bidding to compete in a second Olympic Games together, enjoyed three victories in their group stage, including a tough 17-21, 21-15, 15-11 triumph over 18th seeds Martins Plavins and Haralds Regza of Latvia.

They competed together at London 2012 and each also participated at Beijing 2008; Doppler alongside Peter Gartmayer and Horst with Florian Gosch. 

“We are really happy because we came here to prepare for the Olympics,” said Doppler.

“Here there are night session games under the lights and deep sand and that is important because you don’t have so many occasions in the season when you have night session games. 

“For us it is a very important tournament especially as it our 12th tournament so we have fulfilled the criteria for the qualification process.”

Top seeds Jacob Gibb and Casey Patterson of United States also progressed through to the single elimination bracket despite a defeat to Russia's Oleg Stoyanovskiy and Artem Yarzutkin, 24-26, 14-21.

But third-seeded Chaim Schalk and Ben Saxton of Canada crashed out of the tournament after finishing bottom of a pool won by brothers Matteo and Paolo Ingrosso of Italy.

Home hopefuls Jefferson Santos and Cherif Younousse of Qatar, winners of the opening FIVB World Tour tournament of the year on Kish Island, like this event, open only to men, also bowed out, coming out worst on a three-way tie to finish bottom of their pool.

Another Italian pair won the group in the form of ninth seeds Paolo Nicolai and Daniele Lupo.