Match ends, Real Sociedad 2, Atlético de Madrid 1.
La Liga champions Atletico Madrid remain four points behind leaders Real Madrid as they lost at managerless Real Sociedad after being reduced to 10 men.
It was just Sociedad's second league win of the season, having beaten the table toppers earlier in the campaign.
Atletico top scorer Mario Mandzukic scored a close-range opener before Carlos Vela curled in a leveller.
Visiting defender Guilherme Siqueira was booked twice in three minutes as Imanol Agirretxe headed the winner.
Diego Simeone's men were looking for their fourth straight La Liga win but they showed defensive frailties as they slipped to just a second league defeat of the season to stay in fourth in the table.
The defeat could have been heavier as the hosts had two good penalty appeals turned down, one after a challenge on Vela by Diego Godin and the other for handball against Cristian Ansaldi.
Real Sociedad went into the match in the relegation zone, despite coming from 2-0 behind to beat Real 4-2 in August, but deservedly claimed the points to lift them to 15th.
They are expected to appoint a full-time replacement for Jagoba Arrasate, who was sacked last week, in the next few days.
- 6Martínez Berridi
- 19Berchiche IzetaBooked at 18minsSubstituted forZaldúa Bengoecheaat 56'minutes
- 10Prieto Argarate
- 11VelaBooked at 23minsSubstituted forZurutuzaat 87'minutes
- 18CastroSubstituted forHervíasat 84'minutes
- 14Pardo Gutiérrez
- 20Zaldúa Bengoechea
- 1Moyá Rumbo
- 20Torres BelénBooked at 17mins
- 3SiqueiraBooked at 50mins
- 10TuranBooked at 16minsSubstituted forGriezmannat 85'minutes
- 14Fernández ArenasBooked at 81minsSubstituted forRodríguezat 85'minutes
- 4SuárezBooked at 13minsSubstituted forAnsaldiat 54'minutes
- 6KokeBooked at 80mins
- 8Garcia EscuderoBooked at 51mins
- 5Cardoso Mendes
- 24Giménez de Vargas
- Alfonso Álvarez Izquierdo
- Shots on Target
Second Half ends, Real Sociedad 2, Atlético de Madrid 1.
Pablo Hervías (Real Sociedad) wins a free kick on the left wing.
Foul by Juanfran (Atlético de Madrid).
Pablo Hervías (Real Sociedad) wins a free kick in the attacking half.
Juanfran (Atlético de Madrid).
Xabi Prieto (Real Sociedad) wins a free kick in the defensive half.
Foul by Diego Godín (Atlético de Madrid).
Substitution, Real Sociedad. David Zurutuza replaces Carlos Vela.
Substitution, Atlético de Madrid. Cristian Rodríguez replaces Gabi.
Substitution, Atlético de Madrid. Antoine Griezmann replaces Arda Turan.
Substitution, Real Sociedad. Pablo Hervías replaces Gonzalo Castro.
Goal! Real Sociedad 2, Atlético de Madrid 1. Imanol Agirretxe (Real Sociedad) header from the centre of the box to the bottom left corner. Assisted by Zaldúa with a cross.
Gabi (Atlético de Madrid) is shown the yellow card for a bad foul.
Carlos Vela (Real Sociedad) wins a free kick in the defensive half.
Foul by Gabi (Atlético de Madrid).
Koke (Atlético de Madrid) is shown the yellow card for a bad foul.
Imanol Agirretxe (Real Sociedad) wins a free kick in the defensive half.
Foul by Koke (Atlético de Madrid).
Foul by Carlos Martínez (Real Sociedad).