Subaru World Rally Team principal David Richards said the outcome was proof that the decision to race the car before it was completely ready was the right one.
Petter Solberg took out the second place position in his Subaru just over a minute behind race winner Sebastien Loeb in the Total-Citroen entry.
Fellow Subaru driver Australia's Chris Atkinson was forced into retirement with suspension damage but not before posting the fastest time on the day's opener.
“We wanted to see what the car would do and it felt good this morning, which showed in the speed. We can be faster though as there is still more to come. When we get the package just right we’ll be a lot faster still.” said Atkinson.
After seven rounds, Atkinson is a strong 3rd place in the driver's championship standing.
Ford driver Gigi Galli collected the inaugural Colin McRae Trophy after recording the rally's fastest average speed through a stage - 100.77km/h - though Sunday’s 15.14 kilometre Avlonas stage.
The organising committee of the Acropolis Rally created the award to commemorate the life of McRae, who holds the record for the most outright victories on the event.