The world tennis number one Serena Williams has crashed out of the Madrid Open, beaten in the third round by the Russian Nadia Petrova.
The winner of 12 grand slam singles titles returned to the circuit only recently after a three months injury break following her Australian Open win in January.
In the second round of the mens draw, Sweden's fourth seed Robin Soderling was upset in straight sets by the unseeded Spaniard Nicolas Almagro.
