Top seed John Isner booked his berth in the semi-finals while former US Open winner Andy Roddick was sent crashing out of the ATP Tour\'s Delray Beach International tournament. Isner advanced on Friday with a brisk 6-3, 6-2 victory over eighth-seeded Australian Bernard Tomic. Fellow American and fourth seed Roddick lost his quarter-final in three sets to South Africa\'s Kevin Anderson 2-6, 7-6 (11/9), 6-4. America\'s Isner, ranked 11th in the world, capitalized on four of his five break chances against the 19-year-old Aussie to claim victory in only 56 minutes. Isner, seeking a first title of 2012, will face seventh seeded Anderson who rallied to beat Roddick in a two hour, 33 minute marathon match. Anderson, of Johannesburg, put on an impressive serving display, beating Roddick at his own game. Anderson hammered 11 aces to Roddick\'s eight aces and won 77 percent of his first serve points. Roddick had four double faults overall as he fizzled in the third set, winning just 65 percent of his first serve points. This marked the 25-year-old Anderson\'s second win over Roddick in four career meetings. They faced each other three times last year with Roddick winning the first two before Anderson won in straight sets, 6-4, 7-5, in the round of 32 at the Beijing hardcourt tournament. The 203 centimetre tall Anderson, who is chasing his second career title, raised his record this year to 6-4, while Roddick dropped to just 2-4. Israel\'s Dudi Sela booked his first semi-final berth of the year with a three-set victory over fifth-seeded German Philipp Kohlschreiber. After dropping a second set tie-breaker, Sela responded to post a 6-4, 6-7 (4/7), 6-0 victory. Sela reached his first semi-final since Chennai in 2010. He next faces Australian qualifier Marinko Matosevic, who extended his career best ATP performance with a 3-6, 6-1, 6-1 over 2010 Delray Beach champion Ernests Gulbis.