Not sure what it was listed as but that match Greece played with 5 center backs on the pitch. A back 3 of Kyrgiakos/Moras/Avraam, Vyntra at right back and Sokratis man marking Messi. Essentially it was a 5-4-1 with no wingers and one striker on the pitch, it was one of the most defensive performances I've ever seen from a team and we literally had one decent chance to counter and snatch a goal.
It's not so much the formation but how you counter when you win the ball back, do you break in numbers, or do you hoof a long ball to an isolated striker and hope for a miracle. Greece in 2010 did the latter, I suspect Greece in 2021 will be looking to counter with numbers and actually create something when given the opportunity.