Roars of delight echoed through the Spanish capital as fans welcomed their Argentine coach Diego Simeone and the players in the central city square, Plaza de Neptuno, the traditional victory venue for Atletico fans, who are more used to seeing their derby rivals celebrate just up the road in the Plaza Cibeles.
Atletico Madrid players toured the city from their stadium Vicente Calderon to the city square on a double-decker, open-top bus painted with the words CHAMPIONS on the side, brandishing the silver King's Cup trophy and parting crowds like a red-and-white sea encircling a statue of Neptune, the Roman god of the sea.
"It's great! It's incredible! We deserve it because we have trying and trying for many years and finally it is here," said one fan, 17-year-old emergency health services Carolina de Fente, her face painted in the team colours and hair covered in an Atletico Madrid scarf.
"There are things you have to enjoy once in your life and this is one of them," said 40-year-old salesman Javier Santamaria as supporters broke into a chorus of the team anthem.
"This is the result of work, humility and heart," he added.
Crowds of fans chanted "Champions, Champions" and cried out the name of coach and hero Simeone, who was earlier received at the city hall.
The surprise victory night gave Atletico fans a rare taste of victory over Real Madrid, who had both coach Jose Mourniho and then forward Cristino Ronaldo sent off.
Real Madrid end the season as runners-up to Barcelona in the League and without managing to snare silverware from either the Spanish Cup or the Champions League.
After years of disapointment, thousands of Atletico supporters could not wait for the organized celebrations for the 10th Spanish Cup victory in the team's history, swarming instead to the Plaza de Neptuno even before the final whistle.
Good natured celebrations were transformed into sporadic clashes in the early hours of , however, and some youths burned rubbish containers or threw bottles and stones at police who chased them through the streets.
Police reported 11 arrests and 18 minor injuries.
Spain's press was scathing, however, about Real Madrid's season, almost certainly the final chapter in Mourinho's time in charge.
Madrid sports daily Marca reflected on Mourinho's behaviour on its front page as he didn't go up to collect his loser's medal after being sent from the touchline and admitted afterwards that he "had failed this season."
"Madrid began to run out physically and emotionally," wrote Santi Segurola in Marca. "Madrid's game was defined by the sendings-off for Mourinho and Cristiano, the two flagships of a team that has entered into a lamentable spiral after their elimination from the European Cup.
"Atletico kept their temperament. They didn't concede the opportunity that Madrid looked for. Not this time. They beat their old rival on the best day possible and in the dream scenario."
And there was plenty of criticism laid at Mourinho's door, not just for defeat night, but for his three-year spell in charge which has delivered just the league title last season and the 2011 Copa del Rey in terms of major trophies.