* Former ultra-nationalist bidding to become PM
* Centre-right promising economic overhaul
* Serbia setting out on talks on joining EU (Adds background, context)
By Ivana Sekularac and Matt Robinson
BELGRADE, March 16 (Reuters) - Serbia's centre-right Progressive Party won an outright parliamentary majority on Sunday, according to pollster Cesid, in an election that will cement its grip on power as the ex-Yugoslav republic embarks on talk to join the European Union.
Citing a partial vote-count, Cesid said the Progressives had won "about 50 percent" of ballots cast, which under Serbia's electoral system would translate into an even larger share of seats in parliament.
If confirmed, the haul would be unprecedented in the almost 14 years since Serbia came out of international isolation with the ouster of strongman president Slobodan Milosevic in a popular uprising.
Progressive Party (SNS) leader Aleksandar Vucic, 44, a former ultra-nationalist and once feared Milosevic-era minister who converted to the pro-EU cause in 2008, is likely to become prime minister.
The SNS forced the snap election after just 18 months in coalition government, saying it needed a stronger mandate to overhaul Serbia's shaky finances.
The party's domination owes much to Vucic's personal popularity as the face of a popular anti-crime crusade that saw Balkan retail tycoon Miroslav Miskovic put on trial.
The campaign has struck a chord with many Serbs angry at decades of deep-rooted graft.
Critics, however, are unnerved at the power amassed by a man who up until five years ago was a virulent anti-Western disciple of the Greater Serbia ideology that fuelled the wars of Yugoslavia's bloody demise in the 1990s.
Vucic now says Serbia must follow fellow ex-Yugoslav republics Slovenia and Croatia into the EU, and is advocating root-and-branch reform of the bloated public sector, pension system and labour legislation.
(Writing by Matt Robinson; Editing by Mark Heinrich)