Tennis - Fed Cup - World Group Final - Czech Republic v United States - O2 Arena, Prague, Czech Republic - November 10, 2018 Czech Republic's Katerina Siniakova celebrates winning her match against Alison Riske of the U.S. REUTERS\/David W CernyPRAGUE (Reuters) - World doubles number one Katerina Siniakova helped the Czech Republic to sweep the opening-day matches in the Fed Cup final against defending champions the United States on Saturday, overpowering Alison Riske 6-3 7-6(2). The Czech team, facing a U.S. squad without their top players and fielding three debutantes, will take a 2-0 lead into Sunday as they seek a sixth Fed Cup title since 2011. Siniakova cruised in the first set but fell behind in the second before pulling level. She and Riske battled back and forth then and the American pushed the set to a tiebreak, where Siniakova took control. Barbora Strycova had put the Czechs 1-0 up with a 6-7(5) 6-1 6-4 win over Fed Cup newcomer Sofia Kenin in the opening rubber. Reporting by Jason Hovet; editing by Clare FallonOur Standards:The Thomson Reuters Trust Principles.