The German defender said: "All the teams in the top seven won, no-one dropped any points.
"There was a bit of pressure, the team could feel that, but we responded. I think everyone was expecting at home that we may drop points.
"That was very important, to let the other teams see that Arsenal are alive and that we can respond.
"We look at ourselves and think we are good enough to respond to any challenge they give us.
"It was a strong one, they gave us a good task, but we gave them a little idea of what can happen."
Mertesacker added: "It is really tight at the top.
"There is no chance to drop any points, so we have to show the other teams that we can feel the pressure but we can respond.
"That is really vital. We are really happy with the fighting performance and how resilient we are."
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