Complex sentence: They opened their US Open against the Spanish pairing of Silvia Soler Espinosa and Carla Suárez Navarro, Williamses' lost the first set in a tie-break.
Split into simpler sentences: They opened their US Open against the Spanish pairing of Silvia Soler Espinosa and Carla Suárez Navarro. They lost the first set in a tie-break.