Fired by the goals of Colombia striker Radamel Falcao and inspired by their intensely charismatic Argentine coach Diego Simeone, they are only two points behind leaders Barcelona following Wednesday's 4-2 win at Real Betis.
"Scare for Barca," blared the front-page of Madrid-based sports daily Marca on Thursday next to a shot of Falcao celebrating one of his two goals in Seville.
The Europa League champions, who are known as the "mattress makers" and who last won the title in 1996 with Simeone in the side, have a chance for a rare taste of life at the top if Barca slip up at Sevilla on Saturday and Atletico can win at Espanyol.
Simeone told reporters after the Betis victory he and his players were not about to let their impressive early run go to their heads.
Atletico have yet to test their title credentials against Real or Barca, although their 4-1 destruction of Champions League winners Chelsea in last month's European Super Cup, when Falcao netted a hat-trick, suggests they may have what it takes to succeed on the big occasion.
"We are not paying attention to the points but to the opponents we have to play against," said Simeone, a tough-tackling former Argentina captain who was a fan favourite at Atletico and also had stints at Internazionale and Lazio.
"The Spanish championship is very tough, above all to win away," the 42-year-old added. "Our focus is already on Espanyol."
Falcao's double in Seville took his league tally for the season to seven in five matches, one more than Barca's World Player of the Year Lionel Messi, last season's top scorer with a record 50 goals.
Real forward Cristiano Ronaldo has three and Atletico fans will have to pinch themselves when they see their bitter city rivals, who have had a woeful start to the defence of their title, down in seventh on only seven points.
As Atletico celebrate an impressive start to the season, however, speculation about Falcao's future continues to swirl and the cash-strapped club may be hard pressed to hold on to him, even beyond the January transfer window.
Falcao, who has a minor muscle strain and may be a doubt for Sunday's game, is refusing to feed the rumours and said on Wednesday he was completely focused on Atletico.
"We are just thinking about each match at a time and we are not making any general evaluation," he told reporters.
"The most important thing is the game next and we are just looking to keep getting past the obstacle of each weekend."
Barcelona can make it six wins out of six at Sevilla, before Real Madrid host promoted Deportivo la Coruna on Sunday.
Stuttering Valencia, down in 15th on five points, are at home to Real Zaragoza on Saturday, when fourth-placed Malaga host Real Betis.
Real Mallorca have surprised by climbing up to third, level on 11 points with Malaga and Sevilla, and play at Getafe on Monday.