Top seeded American John Isner was sent crashing out of the ATP and WTA Memphis Open after losing to Austrian Jurgen Melzer 6-3, 7-6 (8/6) in a quarter-final match. Isner, who hammered 48 aces in his first two matches in Memphis, fired 11 aces against Melzer in the 81-minute match at the $1.1 million indoor hardcourt tournament at The Racquet Club of Memphis. Besides Melzer, hard-serving Canadian Milos Raonic, Czech Radek Stepanek and Benjamin Becker of Germany also reached the semis on Friday. In the tie break, Melzer had a double fault to hand Isner a set point, but the Austrian battled back to win the final three points of the set. Isner, who is ranked 13th in the world, also had two double faults and won just 67 percent of his first-serve points. Melzer won 80 percent of his first-serve points, had seven aces and saved both of his break point chances. Third seeded Stepanek also cruised into the semis surviving a first-set tie break then dominating the second set to beat Sam Querrey 7-6 (7/5), 6-0. Stepanek will face Melzer in the semis. Stepanek, who finished second three years ago, posted four service breaks, compared to just one service break for the wild card and 2010 Memphis champ Querrey. Fourth seed Raonic put on an impressive serving display, hammering 26 aces en route to a 6-3, 7-6 (7/3) win over Belgium's Olivier Rochus. "I did a lot of things well today," said Raonic. "I felt like their were a few games where I let up a little bit, but in the end of it there was not much I could do better. "I just wish I could have kept the intensity up. I'm hitting better and I'm playing better tennis match by match. I'm creating my opportunities and taking care of my serve really well." Raonic won 74 percent of his first-serve points and had two double faults in the one hour, 23 minute match. He will next meet Becker who defeated Poland's Lukasz Kubot 7-5, 7-6 (7/5) in a night session quarter-final match. Raonic lost to American veteran Andy Roddick in last year's Memphis final and is coming off his second win of 2012 in San Jose last week. The 21-year-old Canadian was virtually flawless on serve Friday. Raonic, who has not lost a set since the Aussie Open, is trying to win his first ATP 500 title. He now boasts a 14-1 record this season. On the women's side of the draw, fourth seeded Marina Erakovic of New Zealand and Sweden's Sofia Arvidsson will meet in the final after winning their semi-final matches on Friday. Erakovic outlasted Russia's Vera Dushevina 6-1, 4-6, 6-4 and Arvidsson eased past Alberta Brianti, of Italy, 6-3, 7-5.