India's Somdev Devvarmn has stormed into the semi-finals of the singles event at the ATP South African Open Tennis tournament, ousting Rik de Voest of South Africa, 3-6,7-6, 6-1 at the Montecasino entertainment centre in Johannesburg on Friday. Somdev will now face South Africa's local favourite Izak Van der Merwe for a place in the finals. Meanwhile the sixth-seed Adrian Mannarino of France will lock horns with South African, Kevin Anderson in the other semi-final encounter of the singles competition.Earlier on Friday, the Indo-US combine of Somdev Devvvarman and David Martin crashed out of the Doubles event after losing to the Slovakian-Israeli pair of Karol Beck and Dudi Sela 7-6, 3-6, 10-12 in the quarter-final match.