John Isner, the United States number one tennis player, was sent crashing out of the first round of the Australian Open by compatriot Reilly Opelka 7-6(4) 7-6(6) 6-7(4) 7-6(5), on Monday. Ishner, who is Wimbledon semi-finalist, fell at the first hurdle at Melbourne Park for the second year in a row. Last year, he was beaten by unseeded Australian Matthew Ebden. The 21-year-old Opelka broke the ninth seed`s perfect 9-0 winning record against Americans at the Grand Slams in a match featuring 87 aces. "You keep working and put your head down and kind of disappear once I leave here and just work." And, you know, trust that that`s going to pay dividends for me in the future," Isner said. Opelka will next play 102nd ranked Italy`s Thomas Fabbiano in the second round.