Spain's Ariadna Costa Graell and Italy's Elena Francesconi achieved something that no-one has been able to do at the Beach Tennis World Championships - they downed two-time defending champions and top seeds Giulia Gasparri and Ninny Valentini 4-6 6-2 11-9.

The No. 1 players in the world had only lost two matches all year (with one of those defeats being the result of a retirement) and since forming such a strong partnership had never been beaten at the World Championships.

Despite taking the opening set, the favourites were outplayed in the second set before letting a close match tiebreak slip through their fingers much to the disbelief of Costa Grael and Francesconi.

The unseeded duo will now face Brazilian sixth seeds Julia Nogueira and Marcela Vita, who in turn overcame countrywomen Sophia Chow and Vitoria Marchezini in Saturday's semi-finals.

The highest-ranked players left in the women's draw - No. 3 seeds Patty Diaz and Rafaella Miiller - take on Veronica Casadei and Greta Giusti in the other semi.

In the men's draw, the higher-ranked pairings won every match-up on Friday. Venezuela's Ramon Guedez and Carlos Vigon ended Peter Campedelli and Giacomo Gabellini's fairytale run to the quarter-finals with a 6-1 6-3 victory.

After the match, Guedez said: "I feel so good. I lost in the first round at the World Championships for the last two years. We are full of confidence and we are ready to play [Nico] Gianotti and [Mattia] Spoto tomorrow."

The last semi-final sees top seeds and defending champions Michele Cappelletti and Antomi Ramos taking on Theo Irigaray and Thales Santos.