The young leader of Italy's pro-Europe Democratic party has scored a large and sweeping victory, which could change the face of European politics and alter its fragile balance.
Matteo Renzi guided his party to a 40.8% share of the vote, against the 21.2% polled by Beppe Grillo's Eurosceptic Five Star Movement and the dismal 16.8% garnered by disgraced former PM Silvio Berlusconi.
Both Grillo and Berlusconi centred their campaign on a vigorous anti-Europe, anti-Merkel agenda, hoping to echo the stunning results of France's far-right Front National party and Britain's Ukip.
Comedian-turned-politician Grillo had fiercely campaigned for a referendum on the euro.
However the pair were completely overshadowed by 39-year-old Renzi, who produced one of the best showings of any European leader.
The Democratic Party has now the highest number of MEPs among Europe's leftists, with 31 lawmakers.
It beat the 27 from Germany's SPD, and fell just three short of the 34 polled by Angela Merkel's centre-right Christian Democratic Union, the largest single component of the pan-national European People's Party.
The result is seen as an endorsement of Renzi's unelected government, which was created just three months ago after he removed his predecessor Enrico Letta.
Renzi's sweeping plans for economic and political reforms - which include slimming down Italy's bureaucracy, fixing labour laws, creating a more efficient justice system and enforcing a privatisation plan - proved to be successful among Italy's electorate.
The former mayor of Florence appealed to Italy's traditionally moderate electorate, portraying his challenge with oustpoken Grillo - who scored 25.5% in last year's 2013 elections with an anti-establishment agenda - as a "match between hope and anger".
Turnout was among the highest in Europe and the outcome was even more surprising as governing parties were generally penalised across Europe - with the exception of Merkel.
In France, for the first time the Front National overtook all the traditional parties in a national election, coming top with a quarter of the votes cast.
Marine Le Pen, leader of the FN, said that France "no longer wants to be led by EU commissioners and unelected technocrats. They want to be protected from globalisation and take back the reins of their destiny".
But Renzi - a "believer in the European dream" as BBC's Alan Johnston puts it - is keen to stand up and take Eurosceptics on.
"This is Italy's moment. Italy is stronger than the fears that traverse it and it has decided to make a difference in Europe," he said, adding that Italy could now be "a leader, not a follower".