Atletico Madrid coach Diego Simeone thanked the Vicente Calderon faithful for urging his side into what he believes will be a "dangerous and difficult" Champions League quarter-final tie.
Having snatched a 1-0 win in the first leg at San Siro, the Spanish club returned to Madrid to overpower seven-time European champions AC Milan, with Diego Costa scoring twice in a convincing 4-1 victory.
Arda Turan and Raul Garcia bagged the other goals as Atleti ran out 5-1 winners on aggregate, booking their place in the last eight while ensuring there would be no Italian team in the quarter-finals for the first time in five years.
Midway through the first half, Kaka had scored what ultimately proved to be a mere consolation goal for the Rossoneri.
There were over 25,000 red and white flags flying before kick-off at the Calderon and Simeone believes the "beautiful" show of support played a decisive role on Tuesday night.
He told clubatleticodemadrid.com: " I'm happy because this is a group of men who play football in an extraordinary way and have a huge passion for football.
"I am happy with the amount of people who were in the stadium, how nice it looked, with the flags, the kids, all the men and women. It was beautiful to see.
"The fans have been amazing. Things are as they want them to be and how we want them to be.
"When we went out to the field and we saw the flags, it was an extraordinary footballing moment.
"It's not easy to score four goals past Milan, so it was an important victory."
Atleti can now expect to face the likes of reigning European champions Bayern Munich - who on Tuesday night eliminated Arsenal - in the next round.
Simeone is also committed to a battle for the Primera Division title, with the Rojiblancos only three points behind fierce rivals Real Madrid ahead of Saturday's home meeting with Espanyol.
The Argentinian is therefore reminding his players to focus on each match as they come instead of worrying about who they must overcome to reach the Champions League semi-finals.
He added: " It's a good time, but as we are still living through it, there's no time to sit back and enjoy it.
"We are expecting a dangerous and difficult quarter-final.
"We need to rest and prepare properly so we can continue working towards our goals - we know we are doing well."