Real Madrid's fading title hopes were handed what could have been a knock-out blow tonight after the stuttering champions slumped to a 3-2 defeat at Malaga to fall 16 points behind Primera Division leaders Barcelona.
Substitute Roque Santa Cruz struck twice in three second-half minutes to help fourth-placed Malaga heap the pressure on Madrid coach Jose Mourinho, who created a surprise by omitting captain Iker Casillas from his starting line-up.
Madrid dominated the first half but were unable to turn their possession into goals and were made to pay as Isco put Malaga ahead in the 48th minute.
Karim Benzema drew Madrid level midway through the second half but Santa Cruz, who had been on the pitch less than 10 minutes, stunned the visitors by putting Malaga 3-1 ahead with a double strike in the 73rd and 76th minutes.
Benzema pulled another goal back with eight minutes remaining Madrid could not find an equaliser as they slumped to a fourth league defeat of the season - twice as many as they suffered in winning the title last season.
Barcelona continued their record-breaking start to the season when Lionel Messi struck his 91st goal of 2012 in a 3-1 win at Real Valladolid.
The victory at Valladolid's Jose Zorrilla stadium was Barca's 16th in 17 league matches this term and restored their nine-point advantage over second-placed Atletico Madrid, who won 1-0 at home to Celta Vigo on Friday.
Valladolid kept a dominant Barca at bay until two minutes before halftime when Messi, who earlier shook the frame of the goal with a free kick, played Jordi Alba through on the left and Xavi turned his low cross into the net.
Messi uncharacteristically fluffed a simple chance early in the second half but the Argentine World Player of the Year doubled Barca's lead in the 59th minute with a trademark run and finish.
Xavi's clever back heel set the Argentine on his way and Messi dinked the ball between a defender's legs before firing a low shot into the far corner.
It was his 26th La Liga goal of the campaign and his 91st of 2012, extending the calendar year record he broke earlier this month when he overhauled Gerd Mueller's 40-year-old mark of 85.
Javi Guerra pulled a goal back for Valladolid in the 89th minute before Cristian Tello added a third for Barca in added time moments after coming off the bench.