Karolina Muchova turned on the style during a 6-2, 6-2 victory over fourth-ranked Jasmine Paolini at the United Cup on Friday to help the Czech Republic secure a win over Italy and a semifinal spot against the United States. Muchova produced a “tweener” shot between her legs during a memorable exchange in the first set — although she lost that point — as well as an array of slices and other unconventional shots. Muchova improved to 5-0 in her career against Paolini, who was a finalist at the French Open and Wimbledon last year.