Atletico Madrid's 14-year wait for a win over their neighbours continued as Real Madrid came from behind to win 2-1 at the Vicente Calderon.
Radamel Falcao had got Atleti off to a flying start with a simple header from Diego Godin's cross just three minutes in.
However, Real were level nine minutes later when Juanfran turned Angel Di Maria's free-kick into his own goal and Di Maria struck the winner himself with a fine low drive from Karim Benzema's pass just after the hour mark.
Di Maria quickly turned his attentions to Tuesday's Champions League semi-final, second-leg against Borussia Dortmund as Real look to overturn a 4-1 deficit from the first-leg in Germany last week.
"Winning today gives us extra motivation for Tuesday, which we hope will have the best possible outcome," he told Gol TV.
"We haven't given up on the league yet and we are doing things well. (coach Jose) Mourinho put out the team he thought would be best and we gave everything."
With the Dortmund game in mind Mourinho had made eight changes to the side that started in Dortmund with Cristiano Ronaldo not even included in the squad due to a thigh injury.
A makeshift Real side had got off to the worst possible start when after three minutes Diego Lopez spilled Gabi's free-kick and Godin turned the ball back across the area for Falcao to head home at the back post.
Atleti's lead disappeared, though, as Di Maria's free-kick from the right was inadvertantly directed into his own goal by Juanfran.
The game was then disrupted by a flow of yellow cards as referee Miguel Angel Perez produced five in the opening half hour alone.
The only other clear chance of the half fell to Benzema after a fine solo run and pass from Di Maria, but Thiabut Courtois was off his line quickly to block the French international's effort.
Atleti started the second-half just as they had the first and were nearly back in front when Raul Garcia's header was helped onto the bar by Lopez before the keeper collected at the second attempt.
Gabi then missed a glorious chance as he sliced horribly wide after a brilliant one-two with Diego Costa had put him clean through on Lopez before Garcia also saw a driven effort fly just past.
However, the hosts were struck with a sucker punch as Benzema played in Di Maria and his sweet left-footed finish across Courtois gave the keeper no chance.
Real's win reduces Barcelona's lead at the top of the table to 11 points after the Catalans could only manage a 2-2 draw at Athletic Bilbao.
Barca trailed at half-time as Markel Susaeta bundled home Aritz Aduriz's cross, but the introduction of Lionel Messi as a second-half substitute brought the visitors to life as he scored a wonderful individual goal and then set-up Alexis Sanchez to make it 2-1.
Tito Vilanova's men were denied a minute from time, though, as Ander Herrera pounced on Adriano's sloppy clearance to fire past Victor Valdes and give Athletic a share of the spoils.
Meanwhile, Real Zaragoza moved off the bottom of the table with their first win in 2013 as Ruben Rochina's goal three minutes from time gave them a 3-2 win over Mallorca.
The Islanders had gone in front early on through Tomer Hemed, but goals from Paco Montanes and Helder Postiga put Zaragoza in front before Javier Arizmendi looked to have snatched a point for Mallorca eight minutes from time.
However, Rochina's late intervention moves Manolo Jimenez's men up to 18th with Mallorca dropping to the foot of the table.
And Celta Vigo moved out the bottom three as Augusto Fernandez's header gave them a precious 1-0 win at Levante.