Americans Kerri Walsh Jennings, right. and Brooke Sweat are through to the International Volleyball Federation Beach World Tour event in Ostrava, Czech Republic ©Getty Images

Women's top seeds Heather Bansley and Brandie Wilkerson were stunned in round three of the International Volleyball Federation (FIVB) Beach World Tour event in Ostrava, Czech Republic.

The Canadian duo had been favourites for glory and had eased through round two by defeating Austrian pair Katharina Schützenhöfer and Lena Plesiutschnig 21-11, 21-10.

In Kerry Walsh Jennings and Brooke Sweat, though, they had a much sterner test.

Falling a set behind, Bansley and Wilkerson rallied to level at 16-21, 21-19.

The 13th-ranked Americans outlasted their higher-ranked opponents in a nervy deciding set to triumph 21-19 and reach tomorrow's semi-finals.

They will have to be at their best when they take on seventh-seeded Agatha Bednarczuk and Eduarda Santos Lisboa of Brazil.

The duo ousted third-ranked Americans Alexandra Klinemann and April Ross with a 21-18, 21-18 victory.

The second semi-final will be contested by Dutch pair Sanne Keizer and Madelein Meppelink and Brazilians Ana Patricia Silva Ramos and Rebecca Cavalcanti Barbosa Silva.

Keizer and Meppelink edged their Finnish rivals Anniina Parkkinen and Taru Lahti-Liukkonen in a gruelling 28-26 first set before rounding off a 21-15 win in the second.

The Brazilians reached the semi-finals by defeating compatriots Barbara Seixas de Freitas and Fernanda Alves 21-14, 21-10.

Christian Sørum (L) and Anders Mol of Norway are favourites to win the International Volleyball Federation (FIVB) Beach World Tour event in Ostrava, Czech Republic ©Getty Images
Christian Sørum (L) and Anders Mol of Norway are favourites to win the International Volleyball Federation (FIVB) Beach World Tour event in Ostrava, Czech Republic ©Getty Images

In round three of the men's competition, Michal Bryl and Grzegorz Fijalek from Poland earned a semi-final spot by overcoming second-ranked pair Adrian Gavilra and Pablo Herrera of Spain.

The Polish pair dominated their rivals and stormed through with a 21-18, 21-17 victory.

In the semi-finals they face Ondrej Perusic and David Schweiner.

The 16th-ranked Czech duo lost the first set against Brazil's Alison Cerutti and Álvaro Morais Filho but turned the game around to win 13-21, 21-18, 15-11.

Viacheslav Krasilnikov and Oleg Stoyanovskiy will meet top seeds Anders Mol and Christian Sørum of Norway in the last four.

The Russian pair fought back from losing the first set against Brazilians Evandro Gonçalves de Oliveira Junior and Bruno Oscar Schmidt to triumph 14-21, 21-16, 15-12.

Mol and Sørum knocked German pair Julius Thole and Clemens Wickler out with a straightforward 21-18, 21-17 win.