Per Mertesacker has admitted that he lacked focus in his debut season in the Premier League.
The German international told the Sunday Express: "There were quite a few games last season when I didn't have enough focus on tackling. I had to learn it, and learn it quickly, to cope with the physical stuff.
"It was a difficult time for Arsenal when I arrived. They had bought players quickly in a few days, and there was a new city, a new language and a new team for me to adapt to. You need at least one year to feel comfortable with everything.
"I had a lot of disappointments, but I have come back in a stronger way. It gave me a new motivation to prove myself in England."
Mertesacker was part of the Arsenal team that lost 1-0 to Norwich yesterday.