Harry Redknapp has described his return to Portsmouth in 2005 as a 'horrific' experience as he revealed he needed personal security after he controversially became manager of arch-rivals Southampton.
Redknapp admitted his players had been terrified by the occasion in a new documentary entitled Fever Pitch! The Battle for the Premier League, which will be shown exclusively on Paramount+.
He had led Portsmouth to promotion to the Premier League in 2003, before keeping the club in the top flight in their debut season.
His first spell as manager ended in acrimonious fashion with Redknapp having resigned after owner Milan Mandaric appointed Velimir Zajec as the club's director of football.
Redknapp was appointed as Southampton manager by chairman Rupert Lowe weeks after leaving, leading to him being labelled a 'Judas' by Pompey fans.
'We had an amazing relationship, I loved him [Mandaric], but we were both volatile,' Redknapp said.
'Eventually we had a bust-up, thing were festering over a member of my staff that Milan wanted me to change and he wanted to bring a foreign coach in, and we had a fall-out and I walked out.
'Within a week I got a phonecall asking me if I would go to Southampton. Why shouldn't I? I've done nothing wrong, should I not work again, so I took the job.
'As a football manager people say, who do you support Harry? You support whatever team you are at, that is your team. I go to Southampton and I am desperate for Southampton to do well.'
Despite pleas for the fans to remember his achievements at Portsmouth prior to the match, Redknapp required personal security when Southampton visited Fratton Park in April 2005 for the South Coast derby.
Redknapp admitted he had underestimated the rivalry between Portsmouth and Southampton, with his move across the divide adding to an already charged atmosphere.
He revealed the Portsmouth coach had required protection from the SAS on route to the stadium, given the hostility surrounding his return to the club.
'I hadn't realised how bad the rivalry was. I knew it was fierce, but it was fiercer than I ever expected,' Redknapp tells the documentary. 'Going back to Portsmouth it was nerve wracking to be truthful, it wasn't an enjoyable day at all. I think the players were terrified.
'We got the SAS, we've got helicopters flying above following the coach. It was pretty horrific.
'I think the players before they even went on the pitch were scared. It was certainly worse than anything they had ever experienced before or after in their careers, I would imagine.'
Redknapp was greeted by a chorus of boos at the match, which saw Portsmouth cruise to a victory in the derby.
A fourth-minute penalty from Yakubu was added to by Arjan de Zeeuw and a brace from Lomana LuaLua as Portsmouth took a 4-1 lead after 27 minutes, which remained the score at full-time.
The defeat proved another major blow in Redknapp's efforts to preserve Southampton's 27-year stay in the Premier League.
Southampton's fight against relegation is explored in a four-part series on the Premier League produced by Story Films, Studio 99, the production company founded by David Beckham, and All3Media International.
Redknapp later admits he cried in his office following Southampton's eventual relegation, which was confirmed by a final day defeat to Manchester United.
He later resigned as Southampton manager in December 2005 to return to Portsmouth, where he saved the club from relegation from the top flight before famously guiding the club to victory in the FA Cup final in 2008.
All episodes of FEVER PITCH: THE BATTLE FOR THE PREMIER LEAGUE are available from 7th May 2023 exclusively on Paramount+