Seventeenth-seeded Heidrich and Vergé-Dépré beat fifth-seeded Summer Ross and Brooke Sweat of the United States 21-17, 21-16 to open play at the Dutch city's Sportcampus Zuiderpark.

This was followed by a 24-26, 21-17, 18-16 semi-final win over fourth-seeded Agatha Bednarczuk and Eduarda "Duda" Lisboa of Brazil.

Heidrich and Vergé-Dépré are competing in only their third FIVB World Tour event together.

After placing 17th in their first two starts together at FIVB stops in the US and Brazil, the pair have won five-straight matches over higher-seeded pairs at this event. 

"We did not get frustrated after placing so low in the first two events this season," Heidrich said.

"We have been training hard and improving with each session."

Antonelli and Salgado, who are bidding to become only the second women’s team to win a FIVB gold medal after advancing to the main draw via a country quota, earned a spot in the finals by defeating 10th-seeded Melissa Humana-Paredes and Sarah Pavan of Canada 21-19, 21-16.

Playing in only their second FIVB World Tour event together, the 15th-seeded qualifiers opened play by eliminating 11th-seeded Louise Bawden and Taliqua Clancy of Australia with a 21-17, 23-21 triumph.

In the men’s competition, Spain’s Adrian Gavira and Pablo Herrera won three matches today to reach the final.

The duo, who have captured two gold medals on the FIVB World Tour in their previous 86 starts, overcame 11th-seeded Daniele Lupo and Paolo Nicolai of Italy 21-19, 21-16 in the penultimate round.

They earlier beat Brazil’s Geroge Souto Maior Wanderley and Vitor Gonçalves Felipe 33-31, 21-16 before defeating Canada’s Sam Pedlow and Sam Schachter 21-15, 21-19 in the quarter-finals.

"It has been a long day," Gavira said.

"We are really, really tired - we want to rest.

"This is our first final of the season and we hope the first gold medal of the season too."

Standing between the Spanish duo and the gold medal are the Russian pair of Viacheslav Krasilnikov and Nikita Liamin, who also won three matches today.

The seventh-seeds begun with a 21-18, 21-16 victory over Austria’s Thomas Kunert and Christoph Dressler before ousting home favourites and top seeds Alexander Brouwer and Robert Meeuwsen 21-16, 21-14 in the last eight. 

Krasilnikov and Liamin then registered a 21-18, 21-18 win over Switzerland’s Nico Beeler and Marco Krattiger to gain a spot in their third FIVB World Tour gold medal match this season from six events.

The match between Gavira and Herrera and Krasilnikov and Liamin will be their second meeting this season.

The Spaniards beat the Russians in a pool play match at last month’s Rio Open.

Both finals in The Hague are scheduled to take place tomorrow.

The bronze medal matches are also due to be held with Bednarczuk and "Duda" Lisboa facing Humana-Paredes and Pavan in the women's, and Lupo and Nicolai going up against Beeler and Krattiger in the men's.