The Germany international defender helped the Gunners keep a third consecutive clean sheet as they ran out 2-0 victors against Brendan Rodgers' side at Anfield on Sunday
The north London side ran out 2-0 victors against Brendan Rodgers' side at Anfield thanks to goals from summer recruits Santi Cazorla and Lukas Podolski.
And the Germany international revealed the pride amongst his team-mates following the win over the Merseyside outfit.
“We believed in ourselves [against Liverpool] - that was the most important thing and we played fantastic,” he told the club's official website.
“We had to believe a lot, because our squad has had many changes and some important players have moved. We didn't know where we stood, but we are very happy now.
“You could see it in the dressing room directly after the match. We are very proud to play for Arsenal. We had a great opportunity here to show everybody what Arsenal is.
“We now have to focus on our strengths and that is vital for the next few weeks, to stay near the top of the league.
“A lot of challenges are coming after the international break but we are looking forward to them because we are full of confidence. We showed that against Liverpool.”
Arsenal remain the only top flight side who have yet to concede a goal this season.