Arsenal defender Per Mertesacker admits the loss of Robin van Persie to Manchester United was 'hard', but believes the club have now fully recovered from the departure of their captain.
Van Persie was sold to the Red Devils in the summer transfer window of 2012 and his goals ensured the club secured the Premier League title for a 13th time.
The 30-year-old's move to Old Trafford came just 12 months after the previous Arsenal captain Cesc Fabregas had joined Barcelona, and appeared to suggest the Gunners were a club in steady decline.
However, the summer of 2013 represented something of a change in mentality from Arsenal, as Arsene Wenger broke their transfer record to acquire the services of Mesut Özil from Real Madrid.
Arsenal now sit top of the Premier League table after seven games, some six points clear of Van Persie and Manchester United, and Mertesacker believes the north Londoners can continue on their upward trajectory.
"It's hard to say what is different but I think one point is that we didn't lose any player from last season," he told The Guardian.
"It was always a bit hard when we lost [Robin] Van Persie and Alex Song last season, and the year before we lost [Samir] Nasri and [Cesc] Fábregas. We kept the squad [this summer] and there is more quality to come. We have a few injured players who we hope are coming back soon."
Arsenal's season began in seemingly ominous circumstances with a 3-1 home defeat at the hands of Aston Villa but, since that moment, they have won all but one of their matches across all competitions.
The signing of Özil has been a key factor in the club's upturn, and Mertesacker believes his international colleague is the perfect fit for Arsenal.
"Our game hasn't changed, it's more that he [Özil] fits into it," he added.
"His progress is quite well at the moment and I think he will show more and more during the season. You can expect a lot from him."