Per Mertesacker believes Arsenal's compact defence has been a major contributor to the club's positive results heading into the international break.
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The Gunners have leaked just five goals in the opening seven games, giving them the second best defensive record in the league behind leaders Chelsea.
Arsenal defender Mertesacker says that while the club's attack attracts the plaudits, the second half performance against West Ham left no doubts that the backline is laying a strong foundation to win games.
"We could feel in the air it was going to be a tough game," Mertesacker said. "We had to fight a lot, especially in the second half when the crowd became West Ham they had a good advantage.
"But we came back into the game on the counter-attack and afterwards we played well, especially defensively. We won more and more headers which was vital.
"It [Arsenal's defence] can be the difference, it is crucial for us that the defence is winning more games. We just try to keep that in our mind the whole year."
Arsenal suffered their first loss of the season to Chelsea recently, with two goals from dead ball situations exposing the Gunners' biggest frailty.
"We have not conceded a lot of goals during games this year and most have been from set-pieces," Mertesacker said. "We just need to keep concentrating on our defensive level.
"We needed to bounce back after the defeat against Chelsea. It's always good to win in front of an international break. We have good confidence and showed that especially when it was tough in the second half."