(CNN) German Chancellor Angela Merkel's party has comfortably won an election in the small southwestern state of Saarland -- a vote seen as a bellwether for the national election in September.
Merkel's center-right Christian Democrats (CDU) won 40.7% of Sunday's vote, a solid 5.5% increase on four years ago and a convincing win over the center-left Social Democrat Party (SPD,) which only took 29.6%, according to CNN affiliate ARD.
The Saarland elections were widely viewed as a test for the SPD's new leader, former EU Parliament President Martin Schulz, whose criticism of US President Donald Trump's policies appeared to be playing well with voters.
The polls had anticipated a much tighter race between the SPD and CDU.
However, Berlin University political scientist, Oskar Niedermayer, told ARD that Saarland is too small a state to draw direct conclusions from for the upcoming national elections.
Bordering France and Luxembourg, Saarland is home to less than one million people, a fraction of Germany's 80-million strong population.
But Niedermayer said the margin of victory in Sunday's election would give Merkel's party a motivational lift as it heads towards national polls on September 24.
The right-wing, nationalist Alternative für Deutschland (AfD) managed to get 6.2% of the vote and will have three seats in the Saarland parliament.
In an unprecedented result in September, the AfD convincingly beat Merkel's CDU in her home state of Mecklenburg-Vorpommern.
The September election was viewed by many as a referendum on Merkel's immigration policy and a demonstration of the anti-immigrant parties that have gained prominence in Europe.
However far-right populist Geert Wilders was soundly beaten by Conservative Prime Minister Mark Rutte in the Dutch election earlier in March, which was seen as a test of populist right-wing sentiment ahead of the French presidential vote in April and September's German election.