Raphael Varane has warned Barcelona that Real Madrid will be "more united than ever" after a 3-0 LaLiga defeat in El Clasico saw them slip 14 points behind the leaders.

After a goalless first half, Luis Suarez gave Barca the lead before Dani Carvajal saw red for a deliberate handball in the box and Lionel Messi swept home the resultant spot-kick.

Substitute Aleix Vidal capped the scoring in stoppage time at the Santiago Bernabeu, bringing Madrid swiftly back down to earth after a Club World Cup triumph secured their fifth trophy of the year last weekend.

Varane insisted Zinedine Zidane's side will not give up on retaining their LaLiga crown, despite the Catalans extending their commanding advantage over them.

"They were more efficient. When we played well we didn't score and they did, and that was the difference," Varane told beIN SPORTS.

"The result doesn't change that 2017 was very good. We will start 2018 in a very complicated way. We are Madrid and we will keep fighting. We will be more united than ever.

"The first half was very good but the start of the second was fatal for us. We eased off and they scored two goals. The red [card] made everything more difficult.

"It always hurts to lose and more so with this result. We have to improve."