NEW YORK :Former champion Carlos Alcaraz continued his imperious march at the U.S. Open by reaching the semi-finals on Tuesday and staying on course for a potentially high-voltage showdown with 24-times Grand Slam winner Novak Djokovic. The second-seeded Spaniard produced yet another clinical display to beat Czech 20th seed Jiri Lehecka 6-4 6-2 6-4 in the quarter-finals at a sunbathed Arthur Ashe Stadium and secured his spot in the last four without dropping a set this year. The 22-year-old,