Dein has remained in close contact with Wenger since leaving Arsenal after the pair spent 11 largely successful years working together.
Arsenal have played some glorious football in recent seasons, but their last trophy was the 2005 FA Cup and that lack of silverware has heaped the pressure on Wenger.
Happy times: David Dein (left) enjoyed a positive working relationship with Arsene Wenger (right)
Dein told Sportsweek on BBC Radio Five Live: 'Arsene Wenger will admit he has had the most difficult couple of years of his career, for two reasons.
'One is the fact the game is getting more competitive, we have seen more money coming in so the competition out there is more intense.
'Secondly, he has had to contend with the fact he hasn't achieved what he would have hoped to achieve, albeit he has done remarkably well in the quality and style of play.
Last success: Wenger lifts the FA Cup in 2005
'But he himself, and the fans, want to win trophies. Arsene is very focused and very determined. I see him regularly, I see a man who still has as much fire in the belly today as when he started.
'He wants to win. I believe in his ability and I know for a fact he is trying very hard to improve the squad this year and I hope he does it.
'People have got to remember what he has achieved. It is easy in life to get rid of people. Then what?
'How do you follow Arsene Wenger? That is going to be the trick for the board and it is not going to be an easy exercise.'
Dein left Arsenal in 2007 due to 'irreconcilable differences' with the board, linked to his support for the involvement of American billionaire Stan Kroenke.
Kroenke is now the majority shareholder at Arsenal and Dein feels he has some 'unfinished business' at the club.
Askedwhether he has any regrets over introducing them to Arsenal, Dein said:'We are getting on to territory which is very sensitive for me because Ifelt I had something extra to contribute.
'Ihad a great working relationship with Arsene Wenger, I respect him enormously and I think in a way that was unfinished business.
'The regrets I have is not working on a daily basis with Arsene. We had that special chemistry that worked for 11 years.'
Stan the man: Kroenke (centre) is the majority shareholder at Arsenal
Dein was one of the architects of the Premier League and, leading into its 20th season, he has been defending the spiralling player wages and the arrival of foreign owners into English football.
Dein believes the imminent introduction of UEFA's new Financial Fair Play rules will help to address the debt that many Premier League clubs are in.
But Dein warned the authorities will have to enforce the regulations rigorously because he expects some clubs will try and find a way around them.
'There is a train coming down the line at a pretty fast pace and that is called UEFA's Financial Fair Play. That will come in in the next 24 months. That may slow down a lot of clubs' expenditure,' said Dein.
'Saving a club from themselves? I think it may slow them down and bring a bit of discipline.
'Like any new rule it is important it should be respected. We don't want to see it as a licence to cheat, where artificial income is created from outside sources.
'You may well find clubs try and boost their income so they have more opportunity of spending money. When rules are put in people try and find ways around them. I am sure people will try.'
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