Devvarman led 3-1 before De Voest stormed back and won five games on the trot to take the opening set. In the second set, Somdev jumped to a 4-1 lead before De Voest clawed his way back and forced a tiebreaker but the Indian held his nerve to push the match to deciding set.
Somdev, then, shifted into overdrive and clinched the third set for a place in the semis.
Earlier, Somdev and David Martin of United States bowed out of the doubles event after going down 7-6 (7-1), 3-6, 10-12 to Slovakia’s Karol Beck and Israel’s Dudi Sela.
India lose again
In a disappointing result, India ended at the bottom of Pool A in the Fed Cup Asia/Oceania Group I after losing 1-2 against Thailand in their last league match.
It was India’s third consecutive defeat, having lost earlier to China and Uzbekistan.
In the first match, Ashwarya Shrivastav went down to Nicha Lertpitaksincha 2-6, 0-6. Sania Mirza levelled the odds at one apiece with a 6-2, 6-0 win over Noppawan Lertcheewakaran but when paired with Rushmi Charavarthi in the deciding doubles tie, they went down 6-3, 0-6, 5-7 to Lertcheewakaran and Lungnadda Wannasuk.
India will now take on Chinese Taipei in a must-win clash to remain in Group I.