Germany international says he only left Primera Liga giants after realising he was surplus to requirements for Carlo Ancelotti, the manager.
Transfer talk: Arsenal's Ozil was to be on the sidelines at Real Madrid
Ozil saw Gareth Bale complete his transfer from Tottenham Hotspur to the Santiago Bernabeu earlier on Monday before agreeing to move to the Emirates Stadium for a reported £42.4 million (Dh242.3m).
And the Germany playmaker later said in an interview with the German Football Association's official website he agreed to the move after it became clear that he no longer figured in the plans of Carlo Ancelotti, the Madrid manager.
"At that moment [a few days ago], I was certain that I would stay at Real Madrid, but afterwards I realised that the coach and the board no longer had confidence in me," he said.
"I am a player who needs that confidence and the possibility came up to go to Arsenal, which is why I chose to go there."
Now he is looking forward to linking up with international colleagues such as Per Mertesacker and Lukas Podolski in north London, as well as working for Arsene Wenger, Arsenal's German-speaking manager.
"Arsene Wenger showed confidence in me and now I will be able to continue progressing as a player. I want to be on top form for the World Cup," the former Schalke and Werder Bremen player said.
"I spoke to him for a long time on the telephone and he explained to me how he thinks football should be played.
"Naturally, I am delighted to now be able to play with Podolski and Mertesacker. I am really satisfied with this new challenge, I know already that they have brilliant supporters, that the stadium is super and that there is class in the team."
Ozil, 24, is currently with the Germany squad preparing for the World Cup qualifying double-header against Austria on Friday in Munich and the Faroe Islands away next Tuesday.
His Arsenal debut could come in their next Premier League fixture, at Sunderland on September 14.
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