And Wenger has acknowledged just how good United were at that time. We needed a little bit more experience, we need a little bit more of mental aggressiveness, and I knew that sooner or later, it was coming.
"I think Man United fans know that until 2004 for about a decade was between Man United and Arsenal, was between Sir Alex and Mr Wenger and I think that these great teams Arsenal had and they fight shoulder to shoulder with Man United made Man United better and better".
Asked if De Gea's future at Manchester United is under discussion, the Portuguese said in a press conference: "No chance".
Without doubt De Gea is thought of alongside the likes of Manuel Neuer, Gianluigi Buffon and perhaps newer stars Ederson and Alissson as the best in the world. The two matches we played not at the Emirates but at (the) fantastic old stadium (were) unforgettable.
The 27-year-old has been one of United's most consistent performers over the past few seasons.
Arsene Wenger: 'Facing Alexis Sanchez will be strange'
That second wind in Manchester coincided with Arsenal's move to a new stadium and the financial constraints that came with it for a number of years.
Jose Mourinho has defended his decision to sign Alexis Sanchez from Arsenal, despite him enduring a hard start to life at Manchester United. And I don't want to go into individuals.
However, Wenger also hinted that, while he is leaving Arsenal, this will not necessarily be his last meeting with either United or Mourinho, having previously suggested he still wanted to continue coaching. "I want to go peaceful and with Mourinho as well because he is a great manager".
"And I feel happy to say that Paul can be a lot of things, but there's a think I can assure you: he's very polite".
Jose Mourinho has blamed his previous success for the anxiety surrounding Manchester United's trophy-less season, telling ESPN Brazil that winning the FA Cup has become vital for him and his side. "I am always loyal to this club".
"I'll say goodbye to everybody". And as such might not field a strong team against Manchester United, in the hope of picking a Europa League final ticket when they face Atletico Madrid at the second leg of the Europa League semi-final at the Wanda Metropolitano.