Defending champion Czech Republic reached the quarterfinals of the Davis Cup on Sunday after Tomas Berdych won the first reverse singles to clinch the first-round series. Berdych, an Australian Open semifinalist, dispatched Thiemo de Bakker 6-1, 6-4, 6-3 on an indoor hard court at CEZ Arena to give the Czechs an unbeatable 3-1 lead. In the final meaningless match, Igor Sijsling defeated Lukas Rosol 6-3, 6-3 to reduce the Czech overall victory to 3-2 in the best-of-five series. He hit 35 winners to De Bakker’s 18.