The Germany international made the surprise £42.4 million move to the Gunners from Real Madrid in 2013.
Wenger had been in contact with Ozil when he was at Werder Bremen, and the midfielder revealed last year that he approached the Frenchman when he initially decided to leave Real Madrid.
But Wenger admits Ozils transfer, which was officially completed on deadline day, was at risk from Paris Saint-Germain as the French club expressed a late interest in signing the 29-year-old.
The former Arsenal manager has revealed that he was forced to warn PSG president Nasser Al-Khelaifi off making a move on the morning of the transfer being concluded.
It was a big signing, because it was a period where we came a little bit out of our financial restrictions, Wenger told Arsenals official website.
Hes a player who I admired always, who I was in touch with when he went to Real Madrid.
Finally we could do it, it was a change of financial potential at the club 2014-15, we had a bit more resources.
There were big complications because it has to be done quickly.
I think I was on the phone at 2 oclock in the morning and it was not done, at 6 oclock in the morning it was done.
Dick Law and Ivan Gazidis were hard-working on the case.
I was on the phone because we played Tottenham the next day, in the morning when I woke up it was done.
I remember just before I left to the stadium I had a call from the president of Paris Saint-Germain asking me: have you done the deal or not? Because we want to do it.
And I said: please dont touch, its finished.”
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