Karim Benzema scored the winner at the Santiago Bernabeu as Real Madrid battled past Atletico 1-0 to move six points clear at the top of La Liga on Saturday. However, it was Zinedine Zidane's double substitution at half-time that ultimately transformed the Madrid derby which Atletico were dominating. Second-place Barcelona can reduce the gap back to three points by defeating Levante on Sunday while the loss virtually ended Atletico’s hopes, as they fell 13 points off the lead and are now in danger of dropping to seventh place by the end of the weekend. Diego Simeone's Atletico were excellent in the first half, but they failed to hit the target and then struggled to hit back when Real started to get their act together. It was Atletico's fifth match without a win and the worry now is that on current this form, they should be worried about not just the title race but about missing out on Champions League as well. It was a far cry from pre-season when Atletico crushed Real 7-3 and many backed them to be serious challengers. Zidane, who was under pressure then, now sees his Real on a run of 21 games unbeaten. His decision to go back to 4-3-3, with Vinicuis Junior and Lucas Vazquez coming on for Isco and Toni Kroos, proved to be effective. Simeone's side were significantly better in the first half and should have taken one of a handful of decent chances as Vitolo hit Thibaut Courtois, Saul Niguez flashed wide and Angel Correa went past the post after going through one-on-one. Real Madrid's central midfielders looked unsure of their 4-3-2-1 formation. Fede Valverde looked uncomfortable as he spent much of the first half as a right winger. Luka Modric was virtually anonymous in his more advanced role. Zidane's double change was a recognition of Atletico's superiority as he reverted to the more familiar 4-3-3 with Modric deeper in midfield. The move worked immediately as Real dominated the start of the second half. In the 56th minute, Vinicius cut in from the left and slipped in the overlapping Ferland Mendy, whose cross to the back post gave Benzema a simple finish. Interestingly, it was Benzema's first goal against Atletico at the Santiago Bernabeu in all competitions, i.e. after 16 appearances and 34 attempts at goal. Also, he gave gave Real their first home victory over Atletico in the league since 2012. Atletico were weakened shortly before when Alvaro Morata, arguably the best player on the pitch in the first 45 minutes, went off with an injury. He was replaced by Thomas Lemar, whom Simeone expected to be sold in the January transfer window. Real retreated a little, waiting for an Atletico push that never came. Valverde received a standing ovation for a burst forward, an appreciation too perhaps for his brilliant breakthrough season. Another roar of approval greeted the final whistle. Real's form is impressive and they have Eden Hazard, out since November, close to a return; most likely on Thursday in the Copa del Rey quarter-finals against Real Sociedad. Gareth Bale's absence was not related to fitness. The Welshman was left out of the squad despite training for most of the week after an ankle injury. Atletico were without the injured Kieran Trippier, meaning Sime Vrsaljko came in a right-back. January signing Yannick Carrasco was named on the bench, after rejoining from Dalian Yifang the day before.