The visitors appeared to be heading towards their own lofty position of fourth spot after Javi Guerrero nodded Racing into a 23rd minute lead.
Sociedad pressed in vain for an equaliser but were unable to make the breakthrough until Darko Kovacevic turned in the box and slotted home on 74 minutes.
Then, in the dying moments Borja Neru conceded a penalty with a scything challenge which brought him a red card.
After a brief altercation between Kovacevic and Racing keeper Jose Maria Ceballos, Javier de Pedro (pictured) stepped up to dispatch the spot kick into the corner of the net.
Malaga chucked away victory, and their unbeaten record, as they slumped to a 4-3 home defeat to Espanyol.
The hosts raced into a 3-1 lead but Maxi Rodriguez popped up with five minutes remaining to hand Espanyol a precious three points.
Julio Dely Valdes put Malaga ahead after just three minutes from the penalty spot and on six minutes Dario Silva doubled the advantage.
Cyril Domoraud pulled one back but Uruguayan striker Silva grabbed his second of the game, with still only 15 minutes on the clock.
Savo Milosevic reduced the arrears on the hour mark and seven minutes later Raul Tamudo equalised from the spot to set up a tense finish and the comeback was capped by Rodriguez.
Mallorca continued their excellent recent run of form with a convincing 2-0 success at home to Osasuna.
Samuel Eto'o put Mallorca ahead on 58 minutes and midway through the second half Alvaro Novo wrapped up the points.
Sevilla belatedly picked up their first win of the season as an Antonito double secured a 2-1 triumph over Valladolid, who scored a consolation through Gonzalo Colsa's penalty.
