Harry Redknapp quit as Portsmouth boss because chairman Milan Mandaric brought in director of football Velimir Zajec, his ex-assistant Jim Smith has claimed.
Zajec took charge of Pompey for their 1-0 win at Bolton on Saturday
Redknapp ended his reign at Fratton Park on Wednesday, saying that he needed to take a break from the game.
But Smith told Radio Five's Sportsweek programme: "There have been problems in terms of players, what the chairman perceived and what Harry perceived.
"But bringing in Mr Zajec pushed Harry all the way - it was the final straw."
Redknapp had said earlier: "Good luck to Velimir Zajec. He has done what anyone would do but I've decided not to live in the middle of a soap opera.
"One day it's one thing, and the next something else. I want a break from that, thanks."
Smith, who left Fratton Park at the same time as Redknapp, also took a swipe at Mandaric and accused him of conducting his business through the media.
On Saturday, Mandaric denied Redknapp had been involved in transfer dealings - hours after newspaper reports hinted that the former manager had been responsible for £3m being paid in agents' fees.
Smith said: "Harry was never involved in transfer dealings with agents and players - that was all done by the chairman and chief executive Peter Storrie, who will back this up.
"Harry just recommended the players. To take a team from the bottom of the First Division to 10th and 12th in the Premiership - most chairman would have been quite happy to pay that kind of money.
"This has been one of the problems of our stay at Portsmouth. Everything has been done in the newspapers - it should all be done in-house and kept in-house."
Meanwhile, Smith has played down speculation linking him and Redknapp with a move to Southampton.
But he refused to totally rule out the prospect of the management duo moving to Pompey's south-coast rivals.
"This is terrible for the manager there, who's having bad time. I know Steve Wigley and hope he can overcome the problems they have at Southampton," stated Smith.
"But people of the calibre of Harry Redknapp will be mentioned with numerous jobs - that is the nature of the game.
"We're football people. I'd love to manage Sheffield Wednesday because a I'm a Wednesday-ite but that wouldn't stop me going to Sheffield United.
"The amazing thing when we left Portsmouth was that some of the die-hard fans there were actually urging Harry to take the job at Southampton.
"They would like to see him back in football in the area he lived."