Jody Morris has recalled the shock that he and Frank Lampard felt during the Spygate row involving Derby and Leeds.
Police arrived at Derby's training ground in January 2019 after a member of the Leeds staff was spotted in the bushes, spying on Lampard's side ahead of a Championship clash.
Marcelo Bielsa then made the astonishing admission that he had been sending spies to watch all their opponents train that season.
Morris who assistant to Lampard at Pride Park before they joined Chelsea later that year, has spoken about the incident on the Off The Hook with Jimmy Bullard podcast.
He said: 'We were playing Leeds the next night and all of a sudden a police car came into the training ground. Police jumped out of the van and two policeman walked onto the pitch while we were doing tactical work.
'First of all everyone's probably thinking "I hope it's nothing to do with me, your family or anything like that," and then he's walked on and just gone "I'm really sorry we're getting reports that there's someone in the bushes over there".
'You were getting worried because Derby's training ground is huge and for them to get close from where they actually started walking to, they've had to do some amount of graft to get there.
'The players stopped and we've had to wait to when the policeman went in and we're standing about for ages and can't get going because the police are worried.
'All of a sudden they've come back and they've arrested someone in the bushes. He's He's had like bolt cutters and anyway we didn't think too much of it.
'Then later Frank rang me and went "mate, you're never going to believe this. You know that earlier in the training ground with the police car? They've taken the fella back to his car, they've opened it up and it's registered to Leeds United. Is Leeds spying on us? Surely not.'
Later on in the evening, Morris said Lampard got a phone call by the Leeds manager who took full responsibility for what had occured.
He said: 'So Frank answers the phone and Bielsa said 'everything that happened at the training ground, was us, was Leeds United, was me and my staff. I take full responsibility, if you want to talk about it to the press I have no problem. This is how I work from where I'm from.
'So Frank was like hold on you're spying on us in training, really? He doesn't do a lot of interviews in English so you can imagine how the phone call is going and he was trying to relay it in broken English to Frank that yeah it was him.'
Championship clubs wrote to the EFL to conduct a thorough probe and Bielsa personally paid a £200,000 fine in the aftermath.
At a press conference six days after the spy was spotted at Derby's training ground, Bielsa invited journalists so he could present in-depth analysis in the hope of showing his research was so thorough that he gained no advantage from watching Derby train.
Morris said: ''There was loads of press going "do you see the detail he's going into?" yeah he's just showing they watch videos of the other team. Then quite a few things were pointed out like some of the hours he was making out that he was watching some of these players, we was processing and going "I don't think there's enough hours in the day to watch the amount that is being said".
'At the same time, my personal view was if you're so good and he is, he's a legend in the game Bielsa and he's done an amazing job at Leeds. I was just thinking 'do you need to do that
'You get people who say they'll do everything to win and I like that. But you can also go against that and say if you're confident in your players. To be honest we spoke to the security at Derby that happened and it happened both times before we played Leeds.
'First time we found someone in the bushes they thought it was a strange person and just let them go. So both times before we played Leeds, someone was found in the bushes.
'Obviously the old bill were there second time and stopped training. He didn't want to stop training he just wanted information. Each to their own.
After the infamous Spygate row, Leeds fans made a chant poking fun at Lampard following his complaints.
Lampard’s Derby had the last laugh that season when they beat Leeds in the play-off semi-finals, celebrating with a rendition of ‘stop crying Frank Lampard’ at the Yorkshire club’s expense in the dressing room.
But Leeds did not forget and it was among the songs belted out by their players after their promotion was confirmed a year later.'