In a fitting way for the club to pay tribute to club legend Luis Aragones, who passed away a day earlier, David Villa opened the scoring late in the first half and then dedicated his goal to the late coach, with whom he won Euro 2008 with Spain.
Diego Costa settled Atletico's nerves by scoring the second goal with 18 minutes remaining, and then Joao Miranda and substitute Diego Ribas each scored later on to round off an emotional night.
Despite enjoying their most successful league season since they last won the league title in 1996, Diego Simeone's side had not managed to end the weekend top of the table due to the consistency of Barcelona, but capitalised on the Catalans' 2-3 defeat to Valencia to move three points clear at the summit.
Before the game one minute's silence was held in memory of Aragones, Atletico's all-time top goal scorer and coach of Los Rojiblancos for three separate tenures, in which he won one league title and three Copas del Rey.
The stadium remained silent until the eighth minute of the game to mark Aragones' number, and then fans chanted his name.
The Atleti dominated the first half, Costa testing Claudio Bravo in the third minute, and then Villa putting the ball in the net after 12 minutes, although it was ruled offside.
Costa later volleyed over the bar, and then Villa finally broke the deadlock, turning in a cut-back from his Brazilian team-mate.
It was the third goal in as many league games for Spain's all-time top scorer, but he had to be substituted by Raul Garcia only a few minutes later with a thigh injury.
Sociedad's only attempt of the first 45 minutes was a shot from David Zurutuza which was easy enough for Thibaut Courtois to save.
La Real had the hosts under pressure for the opening quarter of an hour by the break, but Simeone's side were lifted by the appearance of Diego Ribas from the bench as he played his first game since re-signing for the club on loan.
The Brazilian would mark his return by getting the final goal of the game, but first two different Brazilians got on the scoresheet.
Costa ran onto a through ball by Raul Garcia on the break and slotted into the bottom corner, grabbing the all-important second goal which ensured the Atleti would not suffer the same fate as against Sevilla a fortnight ago, when they drew 1-1 and passed up an opportunity to go top of the league.
Just two minutes after Costa's goal, Miranda powered in a header from a Koke cross, and then in the 87th minute Ribas entered the area and shot high into the net to cap what had been a sensational night for Los Rojiblancos.