David Moyes' men took the lead in the first minute at the Santiago Bernabeu on Saturday but it did not take long for James Rodriguez's equaliser to level the playing field, with Sergio Ramos putting the Blancos ahead before half-time.
Benzema then scored twice in the latter 45 minutes to ensure a 4-1 victory, but the Frenchman aired his concerns that Madrid are making a habit of needing to come back from behind from conceding early on having needed to do the same at Cordoba last weekend.
"I'm pleased with the goal, but more for the win," the striker told reporters after the match. "We had to win because it was a tough game against a great team. But we were fine.
"We have to be careful conceding early goals, because it is not the first time, but at least we are reacting to them.
"With my second goal, I knew I hit it well but I did not know it would be quite that good! We have secured these three points and now we will prepare for Wednesday."
Real Madrid host fifth-placed Sevilla in midweek, looking to extend their gap at the top of La Liga by winning the game in hand they have on challengers Barcelona and Atletico.
