* Djindjic instrumental in overthrow of strongman Milosevic
* Set Serbia on pro-Western path after decade of war
* Assassination in 2003 set back change
* Serbia only now within sight of EU accession talks (Adds march, quote)
By Matt Robinson
BELGRADE, March 12 (Reuters) - Heads bowed where a sniper struck, the political heirs of Serb strongman Slobodan Milosevic paid tribute on Tuesday to the murdered reformer who led his overthrow and plotted the pro-Western path that they now follow.
It was a gesture loaded with symbolism for Serbia 10 years to the day since the murder of Prime Minister Zoran Djindjic, marked by some 20,000 supporters in a slow march through the capital, Belgrade.
Djindjic was instrumental in the overthrow of Milosevic in 2000 after four lost wars and a decade of isolation during the bloody collapse of Yugoslavia, extraditing him to The Hague where he died in a cell in 2006 on trial for war crimes.
The anniversary finds Milosevic's party and its allies back in power, bidding to lead the biggest economy in the ex-Yugoslavia into talks on joining the European Union having spent much of their political lives demonising the West.
With wartime foe Croatia set to join the EU in July, many Serbs rue the years Djindjic's murder cost them, splintering the already fractious post-Milosevic reform movement and ushering in a period of drift and recalcitrance.
Serbia will not join the bloc until at least 2020, but few in the country now disagree on the goal.
"The murder stopped Serbia for a few years," said columnist Milos Vasic, author of the book 'Assassination of Zoran'.
"But from a historical perspective, the course Zoran Djindjic set is irreversible," he told Reuters. "There's no going back."
Two years in power and still wrestling with the remnants of Milosevic's security apparatus, Djindjic was gunned down in broad daylight in 2003 by a powerful clan of mobsters and former paramilitaries whose arrest was imminent. He was 50 years old.
More than 11,000 people were rounded up in a sweeping crackdown, and 44 were sentenced in 2007 to a total of 378 years in jail for involvement in the murder.
Prosecutors said the plan was to bring hardline nationalists back to power, but Djindjic's supporters say the trial never explored the political backdrop or identified who stood to gain, a lack of clarity that still haunts them.
"The aim was to do what they did - to stop Serbia," said Zarko Korac, Djindjic's deputy at the time. "They wanted to disrupt the course of history."
Thousands of friends, allies and supporters took part in a traditional march in Djindjic's honour, lamenting the return to power of those he helped oust.
"Those who took us into war are supposed to now take us into Europe," said Djurica Beslin, one of some 20,000 in the crowd. "They have neither the strength nor the capacity to take us where we should be."
Prime Minister Ivica Dacic, a wartime aide of Milosevic, and his coalition partner Aleksandar Vucic, bowed before a wreath at the spot where Djindjic was hit by a high-velocity bullet as he stepped from his car to his office shortly after midday.
Neither spoke to reporters.
Only six years ago, Vucic, then part of an ultranationalist opposition party, had opposed plans to rename a Belgrade avenue after Djindjic, declaring it should instead bear the name of Ratko Mladic, the Bosnian Serb wartime commander charged with genocide for the 1995 killing of 8,000 Muslims in Srebrenica.
Now in government, and heading a country where 25 percent of the workforce is jobless and the average monthly wage is 380 euros, Dacic and Vucic have swung behind EU membership as Serbia's best hope of prosperity.
They expect to clinch accession talks in June by settling relations with Serbia's former Kosovo province, where Milosevic went to war with NATO in 1999.
Accession talks would provide a stimulus for reform and send a strong signal of stability to much-needed investors.
Much time has already been lost.
Eloquent and energetic, with a PhD in philosophy from Germany, Djindjic's passion for a modern Serbia tied to the West was replaced by the sombre and increasingly nationalist tone of Vojislav Kostunica.
Kostunica was contemptuous of the United Nations war crimes tribunal in The Hague and reluctant to hunt down Mladic and his political chief Radovan Karadzic. Karadzic was apprehended weeks after Kostunica left office in 2008. Mladic followed in 2011, unlocking the country's bid to join the EU.
But even now, progress is conditioned on relations with Kosovo, where ethnic Albanians broke away in 1999. Djindjic had pressed the West to tackle its unresolved status quickly, but Serbia tried to freeze the issue after his death.
Kosovo declared independence in 2008 and the EU is now mediating talks to improve ties between the two and resolve a de facto ethnic partition between the Albanian majority and a small Serb pocket in the north propped up by Belgrade.
Dacic and Vucic have signalled they are ready to compromise, though Western diplomats and Djindjic's supporters say they are driven less by conviction than by political expediency.
"They are reluctantly following the path Djindjic set," said columnist Vasic. "Kicking and screaming." (Additional reporting by Branko Filipovic; Editing by Angus MacSwan)