In the warm evening, friends and families chanted "Atleti, Atleti" as they thronged around a fountain featuring Neptuno, the god of the sea, which is their traditional victory party venue.

After watching the team end a near two-decade drought by drawing against Barcelona in the Camp Nou to win the league, fans beeped their horns, set off firecrackers, draped themselves in flags, drank beer and danced in the streets of the Spanish capital.

"After waiting 18 years, we have won the league again," said a beaming Javier Requeno, a 48-year-old economist.

Like many fans, he was already looking forward hopefully to the May 24 Champions League final in Portugal when Atletico face wealthier city rivals Real Madrid

"We have had some hard years, we have put up with a lot and now we have to celebrate. So, we are very happy. This is a historic moment for Atleti, especially if we win the Champions League. The truth is, history owes us that," Requeno said.

Police cut off traffic along the main Paseo del Prado avenue and checked party-goers entering the city centre, also deploying vans in nearby sideroads. But in the early stages of the party, the mood was one of joy.

"I feel pure happiness, nothing else," said a smiling 25-year-old Fran Martin, an insurance company employee, who was trying to photograph the dense crowd in the city centre with her smartphone.

"Being an Atletico fan is a day-in-day-out job, going to the ground and then you get the excitement of this."