Britain`s Andy Murray made swift progress into the US Open fourth round as he swept past Brazilian Thomaz Bellucci in straight sets.Murray had needed five sets to win his previous round but saw off 30th seed Bellucci 6-3 6-2 7-5 in the New York night session.The third seed goes on to face South African 14th seed Kevin Anderson in the last 16 on Monday.Murray leads the head-to-head 5-1 and won when they met at Queen`s in June.