The United States clinched its Davis Cup match against Italy with victories yesterday by Pete Sampras and his doubles team-mates. The wins, following an opening day victory by Andre Agassi, gave the US team an unbeatable 3-0 lead. Sampras, the world No 1, deafeated Renzo Furlan 7-6 6-3 6-0. Richey Reneberg and Jared Palmer then beat Stefano Pescosolido and Cristian Brandi 6-1 6-7 (2-7) 6-4 6-3. In Vaxjo, Sweden, yesterday, Jan Apell and Jonas Bjorkman won their doubles match with Austria to clinch a semi-final berth for the home nation, the defending Davis Cup champions. Their 7-5 6-3 6-3 victory over Thomas Muster and Alex Antonitsch gave Sweden an unbeatable 3-0 lead in the best-of-five series and their fourth consecutive trip to the semi- finals.