Michael Ballack believes Mesut Ozil should have stayed at Real Madrid and fought for his place for longer instead of going to Arsenal.
The Germany international moved to north London from Real Madrid for a record £42.5m fee but has failed to live up to expectations as he struggled to adapt to the pace of the Premier League.
The Gunners lost their Champions League round of 16 tie against Bayern Munich for the second year in succession at the Emirates, but the result could have been so different if the former Werder Bremen man had managed to convert the penalty which he had won in the opening minutes of the first-leg.
In an interview with Marca, the former Chelsea star Ballack confessed: "I would have liked to see Ozil more time fighting in Madrid.
"It was a shame, because I am sure that Cristiano Ronaldo and Benzema would have loved him to continue, because Ozil is a very generous player. He started very well, but then it has been hard to adapt, because English football is very complicated.
"He is one of our best players, a large number '10', but does not assume a lot of responsibility in the team. He is a free player on the field, who has great influence on the game, with amazing quality, but sometimes his body language is not what it should be for a player of his class."
Ozil has been backed by commentators and teammates to overcome his initial struggles in English football, and his national team coach Joachim Low believes the playmaker must begin to demonstrate more enthusiasm when things are not going his way.
The German failed to make an impact at the Emirates Stadium and was out injured with a hamstring strain for more than a month. He returned in time for Arsenal's FA Cup win over Hull City, helping the club to their first major trophy since 2005.
Meanwhile, Ballack admits that Real made him an offer to join the club, saying: "In 2002 I was able to sign for Real after the Champions League final.
"I also had an offer from Bayern and finally chose this team because the 2006 World Cup was in Germany and I felt good to be in my country for that appointment. It was very difficult say no to Real Madrid."