Atletico Madrid squandered a chance to all-but wrap up their first La Liga title since 1996 when they slumped to a surprise 2-0 defeat by Levante.
Victory for Atletico in Valencia would have meant they needed only a win at home to Malaga next weekend to secure top spot and render their final match at Barcelona the following week irrelevant.
Team Pl W Pts
1 Atletico Madrid 36 28 88
2 Barcelona 36 27 85
3 Real Madrid 35 26 83
In one of the best seasons in their history, they are also through to the Champions League final to play Real this month thanks to Wednesday's superb 3-1 win at Chelsea's Stamford Bridge stadium.
Simeone's players did not seem to be feeling the effects of their exertions in London and started the Levante match with their usual intensity but fell behind when the ball ricocheted off Filipe's chest at a corner and squirmed over the line.
A dominant Atletico had plenty of chances for an equaliser, including a Filipe shot cleared off the line by Levante defender Loukas Vyntra in the 63rd minute, before Barral controlled a cross from the left and fired past Thibaut Courtois.
Substitute Adrian curled a shot on to a post 13 minutes from time but Levante comfortably held out to climb above Rayo Vallecano to 10th on 45 points.
Tempers frayed at the end and there was a brief bout of pushing and shoving involving players from both sides but it quickly petered out and the disconsolate Atletico players trudged off as the Levante fans celebrated.
However, an own goal from Filipe Luis in the seventh minute and a neat finish from David Barral 21 minutes from time meant Atletico failed to take advantage of Barca's 2-2 draw at home to Getafe.
Valencia hold Real
Real Madrid failed to take full advantage of slip-ups by leaders Atletico Madrid and Barcelona when they needed a Cristiano Ronaldo volley in stoppage time to rescue a 2-2 home draw with Valencia.
A Real win would have put them level on 85 points with second-placed Barca, who drew 2-2 at Getafe, with a game in hand but they stayed third on 83 points with three games left.
Atletico, who like Barca have two matches remaining including the meeting between the teams at the Nou Camp on the final day of the season, are top on 88 points after they lost 2-0 at Levante earlier on.