The choice of Mrs Ciller, 47, a US- educated professor of economics, confounded diplomatic and Turkish political predictions, and proved that even the grassroots of this conservative party was in touch with the new generation of Turks who wanted a young, modern leader open to the outside world.
Overjoyed party activists of all ages danced to Turkish pop music on the floor of an Ankara sports stadium as Mrs Ciller emerged victorious after two rounds of voting among nearly 1,200 delegates to at a party congress. She walked through the second round with 933 votes, after her more old- fashioned rivals, Ismet Sezgin and Koksal Toptan, withdrew after the first round in which they won 320 and 212 votes respectively.
'We have changed Turkish history,' a delighted Mrs Ciller told the cheering congress hall. The contest came after the former incumbent, Suleyman Demirel, moved to the presidency following the death in April of President Turgut Ozal. Mr Demirel said he will ask Mrs Ciller to form a new cabinet, perhaps as early as today.
These are extraordinary achievements not just for a woman in a Muslim country but for a political novice. Mrs Ciller entered active politics only three years ago, and is better known for her glossy image than for the substance of her actions. But there is no doubt about her determination to run the country; Mr Demirel, her mentor, will now have to take a back-seat role.
Mrs Ciller speaks fluent English and unlike her rivals has been a frequent traveller abroad - to France at the invitation of President Francois Mitterrand, to the World Bank in the United States, and to Britain to see Baroness Thatcher, who in many respects is her political role model.
Mrs Ciller knows her economics. She has the backing of a powerful True Path faction leader, Husamettin Cindoruk, the Speaker of Parliament. She makes the right noises for the nationalists and the religious right of the party, getting most applause yesterday for a line about her love of the Muslim call to prayer.
Most importantly, she seems young and dynamic. 'We wanted the most electable leader. We wanted someone who could win us 48 per cent of the vote, not 28 per cent,' said Fenni Eke, a delegate from Ankara. Another delegate added: 'We got together and it turned out everyone wanted Tansu. Nobody was against a woman leader, in fact that was in her favour.'