NEW YORK (AP) — Novak Djokovic has extended his pursuit of the first calendar-year Grand Slam in men's tennis since 1969 by beating the last U.S. singles player at the U.S. Open. Djokovic's 1-6, 6-3, 6-2, 6-2 victory over 20-year-old Californian Jenson Brooksby on Monday night means there are no American men or women in the quarterfinals for the first time in the history of the country's major tennis championship. The tournament has been held since the 1880s. The 99th-ranked Brooksby's tricky style of play gave No. 1 Djokovic fits in the early going and got a packed Arthur Ashe Stadium crowd into the match. But Djokovic turned things around and improved to 25-0 in Slam matches this season.