And it wasn't just the players singing with fans brilliantly in full voice, too.
The boys from Brussels face Panama, Central America's World Cup debutantes, in Sochi.
Lukaku nodded in a sensational Kevin De Bruyne pass and the Manchester United striker then scored a cute chip, though Panama can take heart from a promising display ahead of games against England and Tunisia.
A national holiday was declared after Panama sealed qualification in October and the entire country will come to a standstill as they a play a World Cup game for the very first time. It is very much allowed and that is part of the rules, and you could run a risk of getting a player sent off.
Panama coach Hernan Dario Gomez: "It would have been bad if they had scored more". This is Tunisia's first World Cup match in 12 years but it is still a storied team. Panama will depend heavily on the experience and approach of their manager Hernan Gomez who has previously coached Colombia and Ecuador at the World Cup tournaments.
I believe you play the way you train, and if Belgium train like that, I'm looking forward to watching them play. "It's a source of great pride for us that their sons are showcasing Belgium to the world as an inclusive and dynamic country".
Can Belgium live up to expectations against debutants Panama? "But each game is different, and if we have a good day, maybe we can achieve something".
Results under Martinez have been excellent - Belgium hasn't lost since he took over - but there is a sense that this tournament represents their best chance at World Cup glory.
Not much was known on European shores about Panama's style of play when they confirmed their place in Russian Federation, although three wins in ten qualification matches suggest they are hardly a free-flowing side.
"We were mature, responsible and serious, the commitment of this team is spectacular", the former Everton coach reiterated.
With six players boasting a century of global appearances, nearly half the squad aged over 30 and a Head Coach who has taken two other nations to World Cups, Panama have experience but very little on such a stage. "We already played our first game, already let out all the emotions".